Metal-Organic Frameworks in Monolithic Structures

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Chemical Engineering Journal 171 (2011) 517–525Contents lists available at ScienceDirectChemical EngineeringJournalj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /c ejSynthesis,characterization and hydrogen adsorption on metal-organic frameworks Al,Cr,Fe and Ga-BTBDipendu Saha ∗,Renju Zacharia,Lyubov Laﬁ,Daniel Cossement,Richard ChahineInstitut de recherche sur l’hydrogène,Universitédu Québec àTrois-Rivières,Trois-Rivières,QC G9A 5H7,Canadaa r t i c l ei n f oArticle history:Received 21February 2011Received in revised form 7April 2011Accepted 8April 2011Keywords:Metal-organic framework (MOF)BTB ligand Pore textureSpeciﬁc surface area Hydrogen adsorptiona b s t r a c tBenzenetribenzoate (BTB)ligand is combined with four trivalent metals,Al,Cr,Fe and Ga by solvothermal synthesis to form four different metal-organic frameworks (MOFs),abbreviated as M-BTB,where M stands for the metal.Each of the MOFs is characterized with pore texture,scanning electron microscopic images (SEM),X-ray diffraction (XRD),Fourier transform infra-red spectroscopy (FT-IR)and thermogravimetric analysis (TGA).Pore texture reveals the highest BET surface area belongs to Al-BTB (1045m 2/g)and decreases in the order of Cr >Fe >Ga.Hydrogen adsorption at 77K and up to ambient pressure indicates that Al-BTB adsorbs highest amount of H 2(0.98wt.%)and decreases in the same order as the speciﬁc surface areas.High pressure H 2adsorption at room temperature (298K)and pressure up to 80bar reveals that Fe-BTB adsorbs highest amount of hydrogen (0.51wt.%or 2.75g L −1,absolute)and the adsorption amount decreases in the order of Cr >Al >Ga.© 2011 Elsevier B.V. All rights reserved.1.IntroductionMetal-organic frameworks (MOFs)are highly promising adsor-bents because of their very high speciﬁc surface area,tunable pore size and case-speciﬁc tailoring of basic molecular architec-ture leading to the large and selective adsorption capacities of several gas molecules.A large volume of MOFs has been reported in the literature;most of them were synthesized and decorated accordingly with an aim towards gas storage [1–3],separation [4],heterogeneous catalysis [5],drug delivery [6]or molecular sens-ing [7].Topologically,all the MOFs consist of metal centers,more precisely known as secondary building units (SBUs)connected with each other by the organic molecules,commonly known as organic linkers [8].Different types of metals have been employed and examined for the structure forming capacity of MOFs;typical examples are zinc [9–15,28],copper [16,17],chromium [18–20],aluminum [21,22],iron [23,24],scandium [25],manganese [26],zirconium [27],vanadium [29]or cadmium [42].Organic linker is probably the far most important part in tai-loring the architecture of metal-organic frameworks.The linker molecule plays the role to tune the pore size and speciﬁc sur-face area of the MOFs.Most versatile usages of different organic molecules as linkers were noticed in synthesizing different species of IRMOFs where zinc was employed as part of secondary build-ing units [8,28].Benzenedicarboxylic acid (BDC)or terephthalic∗Corresponding author.Tel.:+18652422221;fax:+18655768424.E-mail address:dipendus@ (D.Saha).acid is most common in synthesizing different species of MOFs,including MOF-5[9,13,28],MIL-53(Cr,Al or Fe)[19,29]or MIL-101[20,30,31].However,the reported large surface area and the maxi-mum gas (H 2and CO 2)uptake is observed for benzenetribenzoic acid (BTB)as organic linker that formed metal-organic frame-work,MOF-177with zinc as SBU former [10–12,14,15,33–35].Besides hydrogen and carbon dioxide,methane [36],nitrous oxide [36]and carbon monoxide [37]adsorption was also exam-ined on MOF-177.In recent time,Furukawa et al.incorporated few other ligands,like 4,4 ,4 -(benzene-1,3,5-triyl-tris(ethyne-2,1-diyl))tribenzoate (BTE),4,4 ,4 -(benzene-1,3,5-triyl-tris(benzene-4,1-diyl))tribenzoate (BBC)or biphenyl-4,4 -dicarboxylate (BPDC)that demonstrated even larger surface area than BTB containing ligands [38].Apart from the usage of pure or only one type of ligand,employing more than one ligand to form a single MOF was reported recently.Koh et al.[39]combined BDC and BTB lig-ands in different proportions to form different species of MOFs and it was reported that between the ratio of 6:4and 5:5of BDC over BTB,a new type of mesoporous MOF was generated and has been named as UMCM-1.Saha and Deng [40]also gen-erated two types of hybrid MOFs consisting of BDC and BTB by employing two different solvents,DMF (N,N,dimethylformaide)and DEF (N,N,diethylformaide).In other work,Koh et al.[41],syn-thesized the hybrid MOF (UMCM-2)with the combination of BTB and thieno[3,2-b]thiophene-2,5-dicarboxylate (T 2DC)in 1:1ratio,that possesses the BET surface area of more than 5000m 2/g.Klein et al.[43]synthesized the hybrid mesoporous MOF DUT-6with BTB and NDC (2,6-naphthalenedicarboxylate)in 3:2mole ratio that possesses high pore volume of 2.02cm 3/g.Despite the ubiquitous1385-8947/$–see front matter © 2011 Elsevier B.V. All rights reserved.doi:10.1016/j.cej.2011.04.019518 D.Saha et al./Chemical Engineering Journal 171 (2011) 517–525Table 1Synthesis conditions of the metal-organic frameworks.MOF identityMetal saltsSalts amount (g)BTB amount (g)Thermal conditionsAl-BTB Al(NO 3)3·9H 2O 0.1710.290◦C,24h Cr-BTB Cr(NO 3)3·9H 2O 0.1820.290◦C,24h Fe-BTB Fe(NO 3)3·9H 2O 0.2700.280◦C,3days Ga-BTBGa(NO 3)3·x H 2O0.2550.2100◦C,24hevidence that BTB ligand could provide high surface area and gas adsorption properties,it was not employed to form MOFs with any other metal,till today.In this work,we combined BTB ligand with four differ-ent trivalent metals,aluminium,chromium,iron and gallium to form four types of metal-organic frameworks.Each type of MOF was performed materials characterization with pore tex-ture,density measurement,scanning electron microscopy (SEM),Fourier-transform infra-red (FT-IR)spectra,thermogravimetric analysis (TGA)and X-ray diffraction to reveal the identity of the crystals.Hydrogen adsorption measurement was performed at 77K and room temperature to examine the hydrogen sorption capacity of those MOFs.2.Experimental methods2.1.Synthesis of Al,Cr,Fe and Ga-BTBAll metal-organic frameworks of this present work were syn-thesized by solvothermal technique.In general,the corresponding metal salts or the metal precursors were dissolved in 25mL ethanol,where as the BTB ligand was dissolved in 10mL N,N-dimethylformamide (DMF)followed by mixing the two solutions and subjecting to thermal treatment.For Ga-BTB,both the pre-cursor and the ligand were dissolved in 35mL of DMF as the Ga precursor was sparingly soluble in ethanol.The exact identity of metal precursor,amounts of reagents and the thermal conditions are revealed in details in Table 1.After the thermal treatment,the crystals were separated from the solution and washed twice with DMF in order to remove any unreacted reagent.Finally,the DMF treated samples were washed several times with chloroform min-imize the DMF level within the crystals and stored inside glovebox under argon atmosphere in closed container.2.2.Materials characterizationsThe materials characterizations techniques employed for each sample include pore textural properties,density measurement,Fourier-transform infra-red spectroscopy (FT-IR),thermo gravi-metric analysis (TGA),scanning electron microscopy (SEM)and X-ray diffraction technique.The pore textural properties were calculated by nitrogen adsorption–desorption study at liquid nitrogen temperature (77K)and pressure up to 1bar in Micromeritics ASAP 2020instrument.The pore textural properties BET surface area and pore size distribu-tion by density functional theory (DFT)were obtained by analyzing the nitrogen adsorption and desorption isotherms with the built-in software in the ASAP 2020surface area and porosity analyzer.The adsorbent samples were degassed ex-situ at 373K for 24h toa bcd10.80.60.40.20Relative pressure (P/Po)N i t r o g e n a d s o r b e d (m m o l /g )10.80.60.40.20Relative pressure (P/Po)N i t r o g e n a d s o r b e d (m m o l /g )10.80.60.40.20Relative pressure (P/Po)N i t r o g e n a d s o r b e d (m m o l /g )10.80.60.40.2Relative pressure (P/Po)N i t r o g e n a d s o r b e d (m m o l /g )Fig.1.N 2adsorption–desorption plot of Al-BTB (a),Cr-BTB (b),Fe-BTB (c),Ga-BTB (d).D.Saha et al./Chemical Engineering Journal171 (2011) 517–525519remove the guest molecules from the samples before the nitrogen adsorption measurements.The FT-IR spectra of the samples were measured in Thermo-Scientiﬁc Nicolet iN10-MX FT-IR chemical imaging microscope within the wave numbers of4000–800cm−1.The sample prepa-rations include grinding and mixing with KBr followed by pelletization before introducing to the laser.Scanning electron microscopy images(SEM)images were recorded by employing JEOL JSM-5500instrument by using an accelerating voltage of18kV.The thermogravimetric analysis(TGA)was performed in Perkin Elmer TGA7Instrument.The temperature ramp rate employed for this study was10◦C/min up to800◦C in an inert gas(Ar)ﬂow.The X-ray data were recorded in Bruker D8Advance X-ray diffractometer with Cu K␣emission( =1.54056˚A).For each sample,the XRD scan was performed from2◦to75◦with0.02◦width and1s count time.Pro-cessing of all diffraction data including structure reﬁnement was performed using JADE8+software supplied by Materials Data Inc. (Livermore,CA,USA).2.3.Hydrogen adsorption measurementHydrogen adsorption at low(up to1bar)pressure and at77K was measured volumetrically in ASAP2020instrument.About 50mg of each of the sample was used in this experiment.The adsor-bent sample was degassed under a vacuum and at373K for24h before the hydrogen adsorption measurement.Ultra-high purity hydrogen(Praxair Inc.)was introduced into a separate gas port of the adsorption unit for the hydrogen adsorption measurements.The high pressure hydrogen adsorption was measured in Sieverts-type volumetric apparatus,built and calibrated in our laboratory.About100mg of sample was introduced within the sample container and it was subjected to room temperature out-gassing at10−3Torr by employing a turbomolecular pump before any measurement.The skeleton density of the samples were mea-sured by admitting ultra-high purity helium gas(Praxair Inc.) in to the system and performing the density measurement at ambient temperature and equilibrium pressure less than20bar in order to minimize the effect of helium adsorption.The tem-perature and pressure of the gas were monitored by employing calibrated Guildline9540digital platinum resistance temperature detector(accuracy=±0.01◦C)and Paroscientiﬁc740digiquartz high accuracy digital pressure gauge(accuracy=0.01%at f.s.).The real gas densities were obtained from the NIST-12standard ref-erence database.The sample skeleton densities were calculated from the linear regression of sample mass versus gas density plots. Hydrogen adsorption isotherms were measured by using ultra-high purity hydrogen gas(Praxair Inc.).The excess gas adsorption was measured at room temperature(298K)and pressure up to80bar. To estimate the order of uncertainties that might arise from our adsorption measurement,we performed a skeleton density and hydrogen adsorption measurement of similar masses of activated carbon AX-21,whose adsorption characteristics are well-known. The maximum uncertainty of our experiments was found to be not more than±3%.The measured leak rate on this system is practically negligible:10−6MPa/s with He gas at4MPa and room temperature. Leak measured using Mathewson Leak hunter plus8066yielded no leak with hydrogen gas at5MPa and room temperature(minimum detectable leak of the instrument is8.1×10−6mL s−1of hydrogen).3.Results and discussions3.1.Materials characterizations3.1.1.Pore texture and densityThe pore texture properties including BET speciﬁc surface area and pore size distribution were calculated from nitrogen Table2Pore texture properties.MOF identity BET SSA(m2g−1)Bulk density, b(g cm−3)Skeleton density,s(g cm−3)Al-BTB10450.30 1.72Cr-BTB5520.54 1.96Fe-BTB3620.33 1.17Ga-BTB620.29 2.865adsorption–desorption plot by employing the built-in software of Micromeritics ASAP2020porosity and surface area analyzer(shown in Fig.1(a)–(d)).The bulk density was measured in ASTM standard D2854-96where as the skeleton density was measured by helium expansion experiment at ambient temperature.The pore texture and density values of all the samples are shown in details in Table2. It is observed that the highest BET SSA(1045m2g−1)were achieved for aluminum(Al)sample.The surface areas decrease in the order of Cr>Fe>Ga.The pore size distribution calculated by density func-tional theory(DFT)for all the samples are shown in Fig.2(a)and (b)for differential and cumulative pore volume,respectively.It is observed almost all the MOFs possess very narrow distribution in the microporous region,though majority of the pore volumes con-tribute in the mesopore region.Al-BTB possesses two peaks,8.58˚A and11.79˚A though the large pore volume arises from pores in the region of120˚A.Cr-BTB shows the presence of pores in8.58˚A and 12.69˚A but also shares large pore volume in less than100˚A.Fe-BTB is having very low pore volume in microporous region of8˚A and 12.69˚A but having very large pore volume in the range of160˚A. Amongst all the MOFs,Ga-BTB shows the lowest available pore volume,narrow micropore in12.69˚A,but larger pore volume in <200˚A.It is also clear that these MOFs posses the micropore width in the range of8–12˚A along with large mesopores which may arise due to possible crystalline defects.The total pore volume is highestabPore width (Å)Differentialporevolume(cc/g-Å)Pore width (Å)Cumulativeporevolume(cc/g)Fig.2.(a)Differential pore size distribution by DFT theory.(b)Cumulative pore size distribution by DFT theory.520 D.Saha et al./Chemical Engineering Journal 171 (2011) 517–525Fig.3.Scanning electron images,Al-BTB (a),Cr-BTB (b),Fe-BTB (c)and Ga-BTB (d).for Al-BTB followed by Cr-BTB,Fe-BTB and Ga-BTB as observed in Fig.2(b).It is noticeable that the speciﬁc surface areas of all the samples are lower than MOF-177[11,12]or other BTB contain-ing hybrid MOFs [39,41,43].Most probably,the presence of two or more interwoven three-dimensional nets within MOF structures lowered their porosity as observed in the case of PCN-6[44]or MOF-14[Cu 3(BTB)2][45].However,the speciﬁc surface areas of Al-BTB is higher than several other mesoporous MOFs reported till today,like JUC-48[42].The Cr-BTB sample attained the largest bulk density of 0.54g cm −3.For all the remaining samples,the bulk density lies in the close region of 0.29(Ga)to 0.33g cm −3(Fe).The skeleton den-sity was observed to be highest for Ga sample (2.86g cm −3).Lower values of skeleton were densities achieved for Al (1.72g cm −3),Fe (1.17g cm −3)and Cr (1.96g cm −3)based samples.3.1.2.Scanning electron microscopy (SEM)The scanning electron microscopic (SEM)images for Al,Fe,Cr and Ga samples are shown in Fig.3(a)–(d),respectively.All the images were taken after outgassing the MOFs at elevated tem-perature.The morphology of the crystallites is not quite well distinguishable for all samples,most probably because of the lower magniﬁcation power of our SEM microscope.For Ga sample,the crystallites look quite close to the hexagonal proﬁle with size range from 0.5␮m in the face to 0.13␮m in width.The crystallites of Fe sample resemble cubic or orthogonal nature with average size 0.33␮m.The exact morphology of Al and Cr samples was not possi-ble to determine with the present SEM image,however,the average size of the crystals could be approximated as 0.1–0.15␮m for Cr and 0.07–0.13␮m for Al samples.3.1.3.X-ray diffractionThe X-ray diffraction patterns of the four samples are shown in Fig.4.It is observed that the sharpest peak of all the MOFsisAngle(2θo)I n t e n s i t y (c o u n t s )Fig.4.X-ray diffraction patterns.D.Saha et al./Chemical Engineering Journal 171 (2011) 517–525521I n t e n s i t y (a .u .)located at around 6◦followed by a shorter peak at an angle of 11◦.There are also some broad peaks located at higher angles of all the samples.Al and Cr-BTB possess the broad peak at an angle 19–20◦,where as Ga sample shows two small but broad peaks at 35◦and 64◦.Al-BTB possesses a broad peak at an angle of 44◦and a small peak at the shorter angle of 3.4◦.For Fe-BTB,two broader peak formations are also located at 33◦–34◦and 44◦–45◦.Unlike MOF-177or UMCM-1,none of our samples shows the largest peak at 4◦–5◦(MOF-177[12])or 2◦–3◦(UMCM-1[39]),however,all the samples possess the largest peak at 6◦–7◦,similar to that of UMCM-2[41].It is also noticeable that almost all of the peaks of each of the pattern are quite broad in nature accompanied by quite heavy noise and low intensity.Most probably,very thin layer of chloro-form was still present in the inter-lattice spaces of crystals that prohibited the penetration of X-ray within it as described by Saha and Deng [32].The wide pore opening of the mesoporous mate-rials may also caused the partial collapse of the crystalline lattice after the removal guest species during the outgassing phase at ele-vated temperature,as suggested by Koh et al.[39]or observed in the XRD pattern of the mesoporous MOF composed of Al III with one or bidentate ligand comprising of six membered aro-matic rings [46].Due to the poor peak proﬁle and possible lack in accuracy in the overall pattern,we did not attempt to index the peaks and hence did not report the crystal phase identiﬁcation data.3.1.4.FT-IR spectraThe FT-IR spectra of the four metal-organic frameworks are pro-vided in Fig.5.The overall patterns are in quite well agreement with other BTB containing MOFs,reported elsewhere [14,47].The sharp peak at 1400cm −1region is attributed to the symmetric stretching of C O bond that belongs to the carboxylate group of the BTB ligand,where as the peak at 1600cm −1is originated from the asymmetric stretching of the same bond [47].The few weak peaks at 1300–1000cm −1can be attributed to the in-plane bend-ing vibrations of aromatic C–H bonds and the remaining smaller angle peaks (1000–800cm −1)could be contributed by the out of plane bending vibration of C–H bonds [14,47].The C C stretch-ing vibration from the benzene ring of the BTB ligand appears as a weak peak at 1520–1570cm −1.Few weak peaks starting after 1600cm −1till 2000cm −1are attributed to the ﬁrst overtone of in-plane and out of plane vibrations of C–H bonds of BTB ligand,where as the second overtone appears at 2600–2100cm −1.Very broad and weak peak formation in the region of 3000cm −1is attributed to the aromatic C–H stretching of the BTB ligand [14].Finally,the absence of any strong peak at 1700cm −1provides the clear indi-0102030405060708090100ab0200400600800w t .%-8-7-6-5-4-3-2-100100200300400500600700800Tempe rature (o C)D i f f e r e n t i a l -w t .% (d w t .%/d t )Fig.6.Thermogravimetric analysis (TGA),linear form (a)and differential form (b).cation of absence of any free carboxylic acid in the MOF samples[14].3.1.5.Thermogravimetric analysis (TGA)The thermogravimetric plots in linear and differential form are shown in Fig.6(a)and (b).From the differential plot,the losses in weight can be localized in the three discrete regions of 50–100◦C,150–250◦C and 500–600◦C.Very minute loss is observed around in the ﬁrst region of 50–100◦C (1–2wt.%)that can be contributed to the desorption of adsorbed gas from their pore spaces.In the sec-ond region,150–250◦C,the cause of mass loss is attributed to the removal of guest species,mostly N,N dimethylformamide (DMF).For Cr,Fe and Ga based samples,the loss is in this region is lim-ited to 6–7wt.%unlike Al species that suffered a signiﬁcant loss of 19wt.%.This higher loss is a clear indication of larger occupancy of guests within the Al based MOF that could provide better pore texture if it were outgassed at elevated temperature and/or with elongated time period.The ﬁnal region of loss at 500–600◦C can be attributed to the disintegration of framework,i.e.,the decomposi-tion of BTB ligand itself.From the differential plot,the loss can be quantiﬁed approximately as 31,15,49and 34wt.%for Al,Cr,Fe and Ga based MOFs,respectively.The ﬁnal residue amount was within 30–45wt.%for all the samples that can be attributed to the oxides of the corresponding metals.The weight loss due to the decompo-sition BTB ligand is much smaller compared to the possible overall proportion of BTB in the MOF resulting in quite higher ﬁnal residue than expected for a metal oxide.Most probably,there was a sig-niﬁcant amount of carbon deposition,originated from the organic ligand,on the metal oxides as the TGA measurement was performed in an inert atmosphere.522D.Saha et al./Chemical Engineering Journal 171 (2011) 517–525Pressure (Torr)H 2 a d s o r b e d (w t .%)Fig.7.Low pressure hydrogen adsorption isotherms.4.Hydrogen adsorption properties4.1.Low pressure hydrogen adsorptionThe low pressure hydrogen adsorption for all the MOFs were measured at liquid nitrogen temperature (77K)and pressure up to 800Torr in ASAP 2020instrument.The hydrogen adsorption isotherms are shown in Fig.7.All the isotherms are typically type-I according to IUPAC classiﬁcations.The highest adsorption is exhib-ited by Al-MOF,around 0.98wt.%,followed by Cr (0.76wt.%),Fe(0.67wt.%)and Ga (0.36wt.%).It is observed that the hydrogen uptake at ambient pressure range was dictated by BET speciﬁc sur-face area as the hydrogen adsorption amount decreases exactly in the same as BET SSA (Al >Cr >Fe >Ga)as observed in Table 2.The lower hydrogen uptake of all of these samples compared to MOF-177or several other BTB containing MOFs can be attributed to the lower porosity of the materials that is probably caused by the interwoven 3D nets within the structures as described earlier.All the hydrogen adsorption isotherms were modeled by four well-known equations,Langmuir,Freundlich,Sips (Langmuir–Freundlich)and Toth models [12,13].The Langmuir isotherm can be written as:q =a m bP 1+bP(1)where q (wt.%)is the adsorbed hydrogen amount,p is the hydro-gen pressure (Torr),a m (wt.%)is the monolayer adsorption capacity and b (Torr −1)is the other Langmuir isotherm equation parameter.Both equation parameters can be determined from the slope and intercept of a linear Langmuir plot of (1/q )versus (1/p ).Freundlich isotherm is given by:q =kP 1/n(2)where k and n are the Freundlich isotherm equation parameters that can be determined by the slope and intercept of ln P versus ln q plot.The Sips (Langmuir–Freundlich)model can be written asq =a m bP (1/n )1+bP (1/n )(3)where a m ,b and n are equations constants.a cb dPressue (Torr)H 2 a d s o r b e d (w t %)00.10.20.30.40.50.60.70.8800700600500400300200100Pressure (Torr)H 2 a d s o r b e d (w t .%)00.10.20.30.40.50.60.70.8Pressure (Torr)H 2 a d s o r b e d (w t .%)Pressure (Torr)H 2 a d s o r b e d (w t .%)Fig.8.Isotherm model ﬁtting,Al-BTB (a),Cr-BTB (b),Fe-BTB (c)and Ga-BTB (d).D.Saha et al./Chemical Engineering Journal 171 (2011) 517–525523Table 3Parameters of isotherm model ﬁtting.Isotherm modelModelparameters Parametervalues (Al-BTB)Parameter values (Cr-BTB)Parameter values (Fe-BTB)Parameter values (Ga-BTB)ARE%(Al-BTB)ARE%(Cr-BTB)ARE%(Fe-BTB)ARE%(Ga-BTB)Langmuir modela m 1.1580.82510.7120.378 1.4561.631.5940.622b0.0060.0090.0100.016Freundlich modelk 0.0660.0840.0910.082 1.7010.8030.4870.367n2.4272.9833.2974.401Sips modela m 1.533 2.473 2.526 1.2880.2510.4140.2390.257b 0.0120.0260.0300.059n1.3322.3582.6723.483Toth model˛T 5.340 4.972 4.919 5.2680.8290.3270.1630.257k T 2.595 1.347 1.0250.463t0.2450.1810.1560.086The Toth model can be given byq =˛T p (k T +p t )(1/t )(4)where ˛T ,k T and t are Toth equation constants.All the equation parameters of Sips and Toth model can be calculated by non-liner regression techniques.The degree of model ﬁtting was compared by the absolute relative error (ARE)percent,calculated asARE%=Nn =1|x exp −x mod |N×100%(5)where x exp is the experimental point,x mod is the modeling point and N is the number of points in the isotherm.These parameters are given in Table 3and model ﬁtting plots are shown in Fig.8(a)–(d)for Al,Cr,Fe and Ga samples,respectively.ARE values conﬁrmed that Sips model ﬁt better for Al-BTB,however,Toth model ﬁts best for the rest of MOFs.4.2.High pressure hydrogen adsorptionThe high pressure adsorption of four MOFs at room tempera-ture (298K)and pressure up to 80bar is shown in Fig.9(a)and (b)for gravimetric and volumetric capacities,respectively.The excess adsorption amount was directly obtained from the instru-ment shown as the symbols in the plots.Assuming the adsorbed the gas density is equivalent to the liquid density of the same species (hydrogen),the absolute adsorption amount can be calculated as [11,12]m abs =m excess1−( (T,P )/ (l ))(6)where (T ,P )is density of the adsorptive gas (hydrogen)at the particular temperature and pressure and (l )is the density of the same gas in the liquid phase.The absolute adsorption was repre-sented as continuous curve in the plots.It is clearly observed that the Fe-BTB performs highest hydrogen uptake both gravimetri-cally (abs:0.51wt.%,excess:0.465wt.%)and volumetrically (abs:2.75g L −1,excess:2.51g L −1).The hydrogen uptake amounts of the remaining samples lie in the similar range,however,minute observation reveals that the uptake capacity decreases in the order of Cr (0.42wt.%,1.38g L −1)>Al (0.25wt.%,0.85g L −1)>Ga (0.27wt.%,0.8g L −1),all absolute amount.It is also noticeable that the hydrogen adsorption increases linearly with pressure similar to that of many other types of MOFs,which are caused by the poor adsorbate–adsorbent interactions at the ambient temperature level.It is evident that the hydrogen adsorption amounts at elevated pressure and at ambient temperature were not controlled by the pore texture properties unlike the adsorption at ambient pressureabPressure (bar)H 2 a d s o r b e d (w t .%)Pressure (bar)H 2 a d s o r b e d (g L -1)Fig.9.High pressure hydrogen adsorption,gravimetric adsorption amount (a)andvolumetric uptake amount (b).and 77K temperature which are quite obvious due to the associ-ated mesoporosity of these MOFs.The signiﬁcant higher adsorption by Fe-BTB over the rest of the MOFs is most probably caused by the possible open or unsaturated metal sites that could be created during the evacuation step by the elimination of one or more sol-vent molecules from the MOF cavities [48].The unsaturated metal sites can increase the electrostatic attraction between hydrogen and partial charges on metal-organic framework atoms thereby dominating the key adsorption mechanism.5.ConclusionIn this work,we synthesized four metal-organic frameworks by the incorporation of benzenetribenzoate (BTB)ligand with four。

一种高收率uio-66金属有机框架材料的制备方法及应用

一种高收率uio-66金属有机框架材料的制备方法及应用（原创实用版3篇）目录（篇1）1.引言2.UIO-66 金属有机框架材料的概述3.制备方法4.应用领域5.结论正文（篇1）【引言】金属有机框架材料 (Metal-Organic Frameworks，简称 MOFs) 是一种具有高比表面积、多孔性、可调结构和化学功能性的晶态材料。

近年来，随着材料科学的发展和应用需求的增加，MOFs 已经成为材料科学领域的研究热点之一。

UIO-66 是一种典型的 MOF 材料，具有良好的性能和应用前景。

本文将介绍一种高收率 UIO-66 金属有机框架材料的制备方法及应用。

【UIO-66 金属有机框架材料的概述】UIO-66 是一种由尿嘧啶和金属离子构筑而成的金属有机框架材料，具有四方对称性、大孔容、高表面积等优点，可应用于催化、吸附、分离、传感等领域。

UIO-66 材料的制备方法对其性能和应用有着重要的影响。

【制备方法】本文介绍的制备方法如下：1.在一定温度下，将尿嘧啶和金属离子 (如 Co2+、Ni2+、Zn2+等) 溶液混合，并加入适量的有机酸 (如乙酸、丙酸等);2.搅拌一段时间后，沉淀出 UIO-66 晶体;3.将晶体分离、洗涤、干燥，得到高收率的 UIO-66 金属有机框架材料。

【应用领域】UIO-66 金属有机框架材料具有广泛的应用领域，包括但不限于以下几个方面：1.催化:UIO-66 材料具有可调结构和化学功能性，可作为催化剂或催化剂载体，应用于各种催化反应;2.吸附:UIO-66 材料具有良好的孔容和表面积，可作为吸附剂，应用于气体吸附、分离和储存等领域;3.分离:UIO-66 材料具有可调结构和化学功能性，可作为分离剂，应用于分离和提纯混合物;4.传感:UIO-66 材料具有良好的传感性能，可应用于各种传感器件的制备。

目录（篇2）一、引言二、UIO-66 金属有机框架材料的概述三、制备方法1.溶胶 - 凝胶法2.水热法3.微波法四、应用领域1.催化剂2.吸附剂3.电化学器件五、总结与展望正文（篇2）【引言】随着科技的发展，新型材料在各领域中的应用越来越广泛，UIO-66 金属有机框架材料（Metal-Organic Frameworks, MOFs）作为一种高收率的新型材料，在催化剂、吸附剂和电化学器件等领域具有广泛的应用前景。

阴离子金属有机框架

阴离子金属有机框架阴离子金属有机框架（anionic metal-organic frameworks，AMOFs）是一种新型的金属有机框架（metal-organic frameworks，MOFs），与传统的MOFs不同，AMOFs中的金属离子带负电荷，而有机配体带正电荷。

这种结构的特殊性质使得AMOFs在催化、吸附、分离等领域具有广泛的应用前景。

AMOFs的独特结构使得其具有许多传统MOFs所不具备的性质。

首先，AMOFs中的金属离子带负电荷，使得其具有更高的稳定性和更强的亲水性。

其次，AMOFs中的有机配体带正电荷，使得其具有更强的亲油性和更好的催化性能。

这些特殊性质使得AMOFs在催化、吸附、分离等领域具有广泛的应用前景。

在催化领域，AMOFs可以作为催化剂载体，用于催化有机反应。

由于AMOFs具有更高的稳定性和更好的催化性能，相比传统的MOFs，其在催化领域的应用前景更加广阔。

例如，一些研究表明，AMOFs可以作为催化剂载体，用于催化酯化反应、氧化反应等，具有更高的催化效率和更好的催化稳定性。

在吸附领域，AMOFs可以作为吸附剂，用于吸附有害气体和有机物。

由于AMOFs具有更强的亲水性和更好的亲油性，其在吸附领域的应用前景也更加广阔。

例如，一些研究表明，AMOFs可以用于吸附二氧化碳、甲醛等有害气体，具有更高的吸附效率和更好的吸附稳定性。

在分离领域，AMOFs可以作为分离剂，用于分离混合物中的有机物。

由于AMOFs具有更好的亲水性和亲油性，其在分离领域的应用前景也更加广阔。

例如，一些研究表明，AMOFs可以用于分离混合物中的芳香烃、酚类化合物等有机物，具有更高的分离效率和更好的分离稳定性。

总之，阴离子金属有机框架是一种新型的金属有机框架，具有更高的稳定性、更强的亲水性和亲油性，以及更好的催化、吸附、分离性能。

其在催化、吸附、分离等领域具有广泛的应用前景，是一种非常有前途的新型材料。

材料科学领域新突破金属有机框架结构

材料科学领域新突破金属有机框架结构金属有机框架结构（Metal-Organic Frameworks，MOFs）是一种由金属离子或金属簇与有机配体通过配位键连接而形成的多孔材料。

近年来，MOFs在材料科学领域取得了许多新突破，被广泛应用于气体吸附、储能、催化反应等领域。

本文将介绍MOF的基本结构和特点，以及其在材料科学领域的新突破。

首先，我们来了解MOFs的基本结构和特点。

MOFs的核心组成部分是金属离子或金属簇，它们通过配位键与有机配体相连。

这种结构特点使得MOFs具有丰富的孔隙结构和调控性能。

MOFs的孔隙结构可通过选择不同的金属和有机配体以及调控配位键的长度和角度来实现。

这种调控性能使得MOFs的孔隙大小和形状可以根据特定应用需求进行设计，从而实现对气体吸附、分离和储存等过程的优化和控制。

其次，MOFs在气体吸附、储能和催化反应等领域取得了许多新突破。

在气体吸附方面，MOFs具有高度可调控的孔隙结构，可以实现对不同气体的选择性吸附。

例如，一些MOFs被广泛应用于CO2捕获和存储，可以帮助减少温室气体排放。

在储能方面，MOFs的孔隙结构可以实现高密度的气体储存，有潜力应用于氢能、天然气等能源领域。

在催化反应方面，MOFs的孔隙结构可以作为催化剂的载体，提供高度可调控的反应活性位点。

这种特点使得MOFs在有机合成、环境保护等领域的催化反应中具有重要应用价值。

此外，MOFs还在其他领域取得了一些新突破。

例如，在药物传输和释放领域，MOFs的孔隙结构可以作为药物的载体，实现药物的控释和靶向传递，提高药物的疗效。

在光催化领域，MOFs能够通过调控孔隙结构和金属离子的能级，实现光催化反应中的高效能量转换。

在环境污染治理方面，MOFs具有高度可调控的吸附和分离性能，可以用于有机污染物和重金属离子的吸附和去除。

然而，尽管MOFs在材料科学领域取得了许多新突破，但也面临一些挑战。

首先，MOFs的合成过程通常需要较高的温度、压力和特定的溶剂条件，制备过程较为繁琐。

金属有机框架材料的设计与合成

金属有机框架材料的设计与合成金属有机框架材料（Metal-Organic Frameworks，简称MOFs）是一种由金属离子或金属簇与有机配体通过配位键连接而成的三维结构材料。

MOFs具有高度可调性和多样性，因此在吸附分离、催化反应、气体存储等领域具有广泛的应用前景。

本文将探讨金属有机框架材料的设计与合成方法。

首先，金属有机框架材料的设计是关键。

设计一个具有理想性能的MOF材料需要考虑多个因素。

首先是金属离子的选择，不同的金属离子具有不同的配位性质和催化活性。

例如，铜离子常用于气体吸附和催化反应，而锌离子则适用于气体存储。

其次是有机配体的选择，有机配体的结构和功能可以调控MOF的孔径大小、表面性质和化学反应活性。

因此，有机配体的合理设计对于构建高效的MOF材料至关重要。

此外，还需要考虑MOF的稳定性和可扩展性，以满足实际应用的需求。

其次，金属有机框架材料的合成方法也是研究的重点之一。

目前，MOF的合成方法主要包括溶剂热法、水热法、气相法等。

溶剂热法是一种常用的合成方法，通过在有机溶剂中加热反应混合物，使金属离子和有机配体发生配位反应，形成MOF晶体。

水热法则是将反应混合物置于高温高压的水中反应，利用水的溶解性和热力学性质来促进反应的进行。

气相法则是通过气相反应将金属离子和有机配体在高温下反应，形成MOF薄膜或纤维。

这些合成方法各有优劣，研究人员可以根据实际需求选择合适的方法。

此外，金属有机框架材料的表征技术也是研究的重要内容。

常用的表征方法包括X射线衍射、扫描电子显微镜、透射电子显微镜等。

X射线衍射可以用于确定MOF的晶体结构和孔隙结构，通过分析衍射图谱可以得到MOF的晶胞参数、晶体结构和孔隙大小等信息。

扫描电子显微镜和透射电子显微镜可以用于观察MOF的形貌和微观结构。

这些表征技术可以帮助研究人员了解MOF的结构性质，为进一步的应用研究提供基础。

最后，金属有机框架材料的应用前景广阔。

由于MOF具有高度可调性和多样性，可以通过调控金属离子和有机配体的选择和合成方法，设计出具有特定功能的MOF材料。

固态锂电池用MOF聚氧化乙烯复合聚合物电解质

第36卷第3期无机材料学报Vol. 36No. 32021年3月Journal of Inorganic Materials Mar., 2021Received date: 2020-04-20; Revised date: 2020-05-05; Published online: 2020-05-20Foundation item: National Key R&D Program of China (2018YFB0905400); National Natural Science Foundation of China (51772315);Science and Technology Commission of Shanghai Municipality (18DZ2280800)Biography: LIANGFengqing(1994–),female,Mastercandidate.E-mail:*************************梁凤青(1994–), 女, 硕士研究生.E-mail:*************************Corresponding author:WENZhaoyin,professor.E-mail:**************温兆银, 研究员.E-mail:**************Article ID: 1000-324X(2021)03-0332-05 DOI: 10.15541/jim20200206MOF/Poly(Ethylene Oxide) Composite Polymer Electrolyte for Solid-state Lithium BatteryLIANG Fengqing 1,2, WEN Zhaoyin 1,2(1. CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China; 2. Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China)Abstract: Solid polymer electrolytes (SPEs) with high flexibility and processability enable the fabrication ofleak-free solid-state batteries with varied geometries. However, SPEs usually suffer from low ionic conductivity and poor stability with lithium metal anodes. Here, we propose nano-sized metal-organic framework (MOF) mate-rial(UiO-66) as filler for poly(ethylene oxide) (PEO) polymer electrolyte. The coordination of UiO-66 with oxygen in PEO chain and the interaction between UiO-66 and lithium salt significantly improve the ionic conductivity (3.0×10–5 S/cm at 25 ℃, 5.8×10–4 S/cm at 60 ℃) and transference number of Li + (0.36), widen the electrochemical window to 4.9 V (vs Li +/Li), enhance the stability with lithium metal anode. As a result, the as-prepared Li symmet-rical cells can continuously operate for 1000 h at 0.15 mA·cm –2, 60 ℃. The results show that UiO-66 filler is effec-tive to improve the electrochemical performance of polymer electrolyte.Key words: composite electrolyte; poly(ethylene oxide); metal-organic framework material; lithium metal battery Lithium-batteries technology can be enhanced by re-placing the liquid electrolytes currently in use with solid polymer electrolytes (SPEs), enabling the fabrication of flexible, compact, laminated solid-state structures free from leaks and available in varied geometries [1]. The SPEs explored for these purposes are ionically conduct-ing polymer membranes formed by complexes between lithium salt (LiX) and high molecular weight polymer containing Li + coordinating groups, such as poly(ethy-lene oxide) (PEO). In PEO polymer electrolytes, with the polymer in amorphous state, Li + is fast transported along with local relaxation and segmental motion of polymer chain [2-3], but the PEO tends to crystallize below 60 ℃. So the conductivity of PEO polymer electrolytes reaches practically useful values (of the order of 10–4 S/cm) only at the temperature above 60 ℃. Numerous attempts for diminishing the polymer crystallinity were made to im-prove the conductivity of the polymer electrolytes, inclu-ding mixing with other co-polymers [4], adding plasticiz-ers [5] and doping inorganic particles [6-7]. Incorporating inorganic materials into polymer matrix is the mostsuccessful approach, which improves ionic conductivity as well as electrochemical stability and mechanical pro-perties. These inorganic materials mainly include nonco-nductive materials, such as SSZ-13[8], Al 2O 3[1], SiO 2[9], and conductive materials, such as Li 0.33La 0.57TiO 3[10], Li 6.75La 3Zr 1.75Ta 0.25O 12[11], and Li 1.5Al 0.5Ge 1.5(PO 4)3[12]. Investigations showed that nanoparticles with Lewis acidic surface properties can more efficiently boost the dissociation of lithium salt and reduce the crystallinity of PEO, thus improving the ionic conductivity [1, 13]. How-ever, the poor contact between inorganic nanoparticle and PEO for the surface energy gap usually leads to in-homogeneous dispersion. Ceramic fillers grafted with molecular brushes [14] and modified with dopamine [15] are endowed with inorganic-organic properties. They are ex-pected to enhance the miscibility with PEO, future im-proving the ionic conductivity and stability of polymer electrolytes.Metal-organic frameworks (MOFs) consisting of me-tal ion clusters and organic linkers are typical nanopor-ous materials, which possess inorganic-organic hybrid第3期 LIANGFengqing,et al: MOF/Poly(ethylene oxide) Composite Polymer Electrolyte for Solid-state Lithium Battery 333property and high specific surface area, thus being ideal fillers to polymer electrolytes. In 2013, Y uan, et al.[16] used Zn4O(1,4-benzenedicarboxylate)3 metal-organic frame-work(MOF-5) as filler for PEO electrolyte obtaining high ionic conductivity of 3.16×10–5 S·cm–1 (25 ℃) due to the uniformly dispersion. But the weak metal-organic coordination bonds of MOF-5 are easy to be attacked, leading to crystal transition or structure collapse and poor stability for lithium battery.In this work, nano-sized UiO-66, one of the extensive investigated MOFs, was introduced as filler into PEO electrolyte. The UiO-66 with outstanding hydrothermal and chemical stability does not contain transition metals which provide redox-active centers, so the electronic conduction can be avoided when contact with metallic Li.1 Experimental1.1 Synthesis of nano-sized UiO-66Nano-sized UiO-66 was synthesized according to the reported two-step synthesis[17]. (1) 207 mg ZrCl4 (98%, Aladdin) was dissolved in 40 mL N,N-dimethylformamide (DMF) (99.9%, Aladdin) under stirring, and the solution was heated to about 120 ℃for 2 h. Then 1 mL acetic acid was added and stirred for additional 0.5 h at 120 ℃.(2) 147 mg 1,4-benzenedicarboxylic acid (H2BDC) (99%, Aladdin) was added into the solution. And the resulting mixture was introduced into a 50 mL Teflon-lined stain-less-steel autoclave and placed in an oven at 120 ℃ for 24 h. After cooling to room temperature, the resulting precipitates were centrifuged, washed with DMF, puri-fied in methanol and then dried at 60 ℃ under vacuum for 24 h.1.2 Preparation of UiO-66/PEO composite polymer electrolytes (CPEs)PEO (M w = ~600,000, 99.9%, Aladdin) was dried at 50 ℃, and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) (99%, Aladdin) was dried at 100 ℃ for 24 h under vacuum and stored in an Ar-filled glove box. Firstly, LiTFSI was dissolved in anhydrous acetonitrile, and UiO-66 and PEO were added under magnetic stirring to afford homogeneous solution, in which the molar ratio of EO : Li+ was kept 16 : 1, and the content of nano-sized UiO-66 fillers was designed to be 0, 5%, 10%, 15%, 20%, 25%, naming the corresponding electrolytes as SPE, CPE-(5%, 10%, 15%, 20%, 25%). Afterwards, the solu-tion was cast on polytetrafluoroethylene template to vo-latilize the solvent at ambient temperature. Finally, the membranes were dried at 60 ℃for 12 h under vacuum to volatilize the residual solvent. 1.3 Sample characterizationThe crystalline structures of ingredients were col-lected from X-ray diffraction (XRD) with Cu-Kα radia-tion (λ=0.1542 nm) at room temperature (2θ=5°–50°) with the step of 0.1 (°)/s. The structure morphologies of UiO-66 and CPE were revealed by the scanning electron microscopy (SEM, Hitachi, S-3400N).1.4 Electrochemical measurement and cells assemblyThe ionic conductivity was measured at temperature from 25 to 80 ℃in symmetric cell with stainless steel (SS) electrodes by the AC impedance analysis (Autolab, Model PGSTAT302N) in the frequency range from 1 Hzto 1 MHz and at an amplitude of 50 mV. Linear sweep voltammetry (LSV) was employed to examine the elec-trochemical window in SS/electrolyte/Li cells, conduct-ing from 3 to 5.5 V at a scan rate of 10 mV/s. The trans-ference number of Li+ (t+) was tested in Li/electrolyte/Li cells and calculated according to t+ =00(Δ)(Δ)I V I RI V I R∞∞∞--, where ΔV is the applied DC polarization voltage (10 mV),I0 and I∞are the initial and steady current values during polarization, respectively. R0 and R∞are the resistance values before and after polarization, respectively. For inhibition ability of lithium dendrites growth test, a symmetric cell with solid electrolyte sandwiched be-tween two lithium metal electrode was assembled, and the test was carried out at 60 ℃。

金属有机框架物简介

金属-有机框架化合物简介金属-有机框架化合物(Metal-Organic Frameworks，MOFs)通常是指以有机配体为连接体(linkers)和以金属离子或簇为节点(nodes)，通过配位键组装形成的具有周期性结构的配位化合物。

由于MOFs材料在荧光、催化、气体吸附与分离、质子导体、药物运输等方面具有潜在的应用价值，近十几年来，发展非常迅速，大量结构新颖的MOFs被不断的设计合成出来。

随着现代配位化学和晶体工程的发展，MOFs之间的键合作用已经不再仅局限于配位键作用，还囊括了其他作用力，比如：氢键作用，范德华力，芳香环之间的π-π作用等。

这些丰富的作用力使得MOFs结构和功能更加多元化、复杂化。

近几年来，计算机技术和仿真技术被应用到MOFs的研究中，在它们的帮助下，越来越多的新型MOFs材料不断的被合成出来。

与传统的多孔材料相比，MOFs材料的优势在于结构和功能的可设计性和调控性。

在理想情况下，通过合理设计配体和选择金属离子构筑的次级构建单元(SBUs)，就可以合成目标结构和功能的MOFs。

虽然，目前每年有很多结构新颖性能特别的MOFs被合成报道，然而，在很多情况下，看似合理的设计，却很难实现。

这与MOFs的自主装过程有关。

在MOFs的合成过程中，除了配体和金属离子的影响外，还有其他的影响因素，比如：反应温度、溶剂、pH值、压力、配体和金属盐的比例与浓度等，每一个反应条件的改变，都有可能影响MOFs 的自主装过程，从而影响MOFs的结构，进而可能影响MOFs的性能。

总之，在通常情况下，根据金属离子构筑的SBUs和有机配体的几何构型可以预测MOFs最终的框架结构。

例如：平面方格结构可以通过4-连接平面构型SBU和直线型2-连接配体形成，如：MOF-118；类金刚石结构则可以通过四面体构型的4-连接SBU和直线型2-连接配体形成；立方结构框架则可以通过6-连接的SBU和直线型2-连接配体形成，如：MOF-5；T d八面体结构可以通过3-连接配体和轮桨状的4-连接SBU构筑，如：HKUST-1 (Figure1.1)。

金属有机框架ZIFs的应用研究进展

第21期王立花，等:金属有机框架ZIPs的应用研究进展-61-金属有机框架ZIPs的应用研究进展王立花，李涛，雷婷，江世智(大理大学药学院，云南大理671000)摘要：目的:通过整理分析近几年金属有机框架ZIPs(Zeolitic Imidazo—te Frameworks,ZIPs)的应用研究,为以后研究提供参考&方法利用期刊检索平台，检索金属有机框架ZIF的相关应用，尤其是在医药研究及环境科学领域&结果:通过对文献进行整理分析发现，金属有机框架可进行结构修饰，在各个领域都有着广泛的应用,在我们所涉及到的医药领域中发挥着重要的作用&结论:金属有机框架材料ZIPs在肿瘤癌细胞的治疗及环境治理,生物分子保护传递等方面具有很大的应用前景,对以后的研究提供较大的参考价值&关键词:金属有机框架'可修饰性'研究进展中图分类号：0643.36；06413文献标识码：A文章编号：1008-021X(2020)21-0061-03Research Progress in the Application of Metal Organic Framework ZIFsWang LiPua,LI Tao,Lei Ting,Jiang Shizhi(Co e e geoophaemacy，DaeoUnoeeesoty，Daeo671000，Chona)AbstracC:Objective:Provides a reference for future research by oryanizing and analyzing the application research of metal oryanic framework ZIPs in recent years.Methods:Based on the journal search pahorm,applications of the Metal Oryanic Framework ZIPs were searched,especial—in the field of pharmaceutical research and environmental science.Results Through the analysis of the —terature,we found that the ZIPs of metal oryanic framework can be structural—modified and had a wide range of applications in various fielUs,p—yed an important role in the medical field we were involved in.Conclusions:The metal-oryanic framework ZIPs has great application prospects in the Weatwent of cancer cells,environmental governance,and the protection of biomolecuXs, etc.,and provides a great reference value for future research.Key words:mGtaeoeganocoeamGwoek'modoooaboeoty'eGsGaech peoge s金属有机骨架材料因其结构的特殊性在很多领域内都有着广泛的应用，沸石咪瞠酯骨架材料(Zeoli-e Imidazolate Frameworks,ZIPs"是金属有机框架材料的一个亚基［1］,不仅有金属有机骨架的作用还具有“分子筛”的功能0i Mi Yaghi 教授等⑶合成了多种ZIPs用于对C02的捕获研究，随着对该材料的不断探索，国内外大量研究显示其在医药研究及环境保护等方面同样有广阔的应用前景，根据对该材料的配体进行修饰合成可不断的对材料应用进行改性探索,为今后的研究提供新的方向及思路&1金属有机框架ZIPs的功能简介金属有机框架，是一种与含有潜在空穴的有机配体的配位网络⑷。

《典型金属有机框架材料的植物毒性效应及机制研究》范文

《典型金属有机框架材料的植物毒性效应及机制研究》篇一一、引言随着科技的进步与新材料领域的不断发展，金属有机框架材料（Metal-Organic Frameworks, MOFs）因具有高度多孔、高比表面积以及结构多样性等特点，已广泛应用于催化、分离和储存等领域。

然而，随着MOFs的广泛应用，其潜在的生态毒性问题逐渐引起人们的关注。

本篇论文旨在探讨典型MOFs材料对植物的毒性效应及其作用机制，为MOFs的环境安全性评估提供理论依据。

二、文献综述近年来，关于MOFs的生态毒理学研究逐渐增多，但主要集中在动物模型上，针对植物的毒性研究尚处于起步阶段。

已有研究表明，MOFs材料在植物生长介质中可能对植物产生不利影响，如抑制植物生长、影响光合作用等。

此外，MOFs材料的组成元素如锌、铜、铁等也可能对植物产生毒性效应。

因此，深入研究MOFs对植物的毒性效应及机制具有重要意义。

三、实验方法本研究选取了几种典型的MOFs材料，通过水培实验法，探究其对植物的生长影响及生理生化变化。

具体实验步骤如下：1. 选取典型MOFs材料，制备不同浓度的MOFs溶液；2. 选择生长状况良好的植物种子，进行水培；3. 将不同浓度的MOFs溶液分别加入水培容器中，设置对照组；4. 定期观察并记录植物生长情况，包括株高、根长、生物量等；5. 采集植物叶片样本，进行生理生化指标的测定，如叶绿素含量、光合速率等；6. 结合显微镜技术和分子生物学技术，分析MOFs对植物细胞结构及基因表达的影响。

四、实验结果与分析1. 生长影响：随着MOFs溶液浓度的增加，植物的生长受到明显抑制。

具体表现为株高、根长、生物量等指标的降低。

这说明MOFs材料对植物生长具有负面影响。

2. 生理生化变化：MOFs处理后，植物叶片的叶绿素含量降低，光合速率下降。

这表明MOFs可能影响了植物的光合作用。

3. 细胞结构变化：通过显微镜观察发现，MOFs处理后，植物细胞结构发生异常变化，如细胞壁增厚、细胞质收缩等。

Metal-OrganicFrameworks有机金属框架

A Series of Two-Dimensional Metal-Organic Frameworks Based onthe Assembly of Rigid and Flexible Carboxylate-Containing MixedLigands with Lanthanide Metal SaltsXing-Jing Zhang,†,‡Yong-Heng Xing,*,†Zheng Sun,§Jing Han,†Yuan-Hong Zhang,†Mao-Fa Ge,§and Shu-Yun Niu†College of Chemistry and Chemical Engineering,Liaoning Normal Uni V ersity,Huanghe Road850#,Dalian116029,China,College of Chemistry,Jilin Normal Uni V ersity,Shida Road1301#,Siping136000,China,Institute of Chemistry,the Chinese Academy of Sciences,Beijing100080,P.R.ChinaRecei V ed June5,2007;Re V ised Manuscript Recei V ed July23,2007ABSTRACT:A series of lanthanide metal-organic frameworks,[Ln2(Suc)0.5(BC)3(OH)2](Ln)Tb(1),Eu(2),Sm(3),Pr(4); H2Suc)succinic acid;HBC)benzoic acid),have been synthesized by the reaction of nitrate salts of Ln(III)with succinic acid and benzoic acid under hydrothermal conditions and were characterized by elemental analysis,IR spectroscopy,and single-crystal X-ray diffraction.X-ray diffraction analyses reveal that they exhibit the same two-dimensional(2D)architecture and crystallized in triclinic space group P1h for complexes1-4.Infinite inorganic walls were formed by lanthanide ions,µ3-OH,and an edge-sharing “...Ln-O-C-O-Ln...”chain,which link to each other through the carbon atoms of the succinate anions on the[110]plane and phenyl groups of the benzoic acid ligands on the[101]plane,leading to a two-dimensional open framework structure.The thermogravimetric analysis of1-4and photoluminescent properties of1and2are discussed in detail.IntroductionThe construction of metal-organic frameworks(MOFs) through coordination of metal ions with multifunctional organic ligands has attracted great interest over the past decade not only because of their intriguing topological structures but also because of their potential application as functional materials.1These materials can be applied in magnetism,zeolite-like catalysis activity,gas storage,ion exchange,and optical properties,etc.2 Different type of ligands have been used for the preparation of such complexes.Especially,carboxylate-containing ligands have drawn much attention because of the diversity of the coordina-tion modes of carboxylate groups to metal atoms.So far, extensive work has been carried out using rigid carboxylate-containing ligands;for example,benzoic acid3and its derivative ligands4-11have been widely used in the coordination complexes of rare-earth metals.The benzoate derivative ligands involve (i)2-nitrobenzoic acid,3-nitrobenzoic acid,and4-nitrobenzoic acid;4(ii)3-methoxybenzoic acid(m-MOBA)and2,3-dimethox-ybenzoic acid(2,3-DMOBA);5(iii)aminobenzoic acid;6(iv) hydroxylbenzoic acid;7(v)1,2-benzene dicarboxylic acid(o-H2BDC),81,3-benzene dicarboxylic acid(m-H2BDC),9and1,4-benzene dicarboxylic acid(p-H2BDC);10(vi)1,2,4,5-benzene-tetracarboxylic acid(H4BTEC);11and other more complicated benzoate derivative.12The majority of complexes with these ligands formed2D layer or3D network structures.At the same time,it is found that some flexible carboxylate-containing ligands for the flexibility and conformational freedoms of the ligands may offer various possibilities for construction of frameworks with unique structures and useful properties. Succinic acid ligand is one of the flexible carboxylate-containing ligands,and a large number of coordination polymers of Ln-succinate13have also been synthesized,such as[Sc2(C4H4O4)2.5-(OH)];13a[Eu2(C4H4O4)3(H2O)2]and[Tb2(C4H4O4)3(H2O)2]‚H2O;13c[Pr(H2O)]2[O2C(CH2)2CO2]3‚H2O;13e and[Sm2(C4H4O4)3(H2O)2]‚0.5H2O,13f etc.Among the complexes reported above,all contain just one type of carboxylate compound as ligand with different coordination modes to form various structures(2D and3D).In order to further understand their synthetic regularity and various coordination modes,as well as the influence of the carboxlate group from mixing ligands(rigid and flexible)on structures,it is necessary to explore and design a series of new complexes with more complicated structures for improving desirable properties.To the best of our knowledge,the complexes from the assembly of a series of bent rigid and flexible organic ligands (benzoic acid and succinic acid as mixed ligands)with lan-thanide metal salts have not been observed so far.14As an in-depth analysis and part of our systematic investigation of self-assembly based on bent rigid and flexible organic ligands,we herein present the synthesis of four two-dimensional metal-organic framework complexes,[Ln2(Suc)0.5(BC)3(OH)2](Ln )Tb(1),Eu(2),Sm(3),Pr(4);H2Suc)succinic acid;HBC )benzoic acid).The thermal stability and luminescent proper-ties have also been investigated.Experimental SectionAll chemicals purchased were of reagent grade or better and were used without further nthanide nitrate salts were prepared by dissolving lanthanide oxides with6M HNO3and then evaporating at100°C until the crystal film formed.The infrared spectra were recorded on a JASCO FT/IR-480PLUS Fourier transform spectrometer with pressed KBr pellets in the range200-4000cm-1.The lumines-cence spectra were reported on a JASCO FP-6500spectrofluorimeter (solid).The elemental analyses were carried out on a Perkin-Elmer 240C automatic analyzer.Thermogravimetric analyses(TGA)were performed under N2atmosphere at1atm with a heating rate of10°C/min on a Perkin-Elmer Diamond TG/DTA.Synthesis of[Tb2(Suc)0.5(BC)3(OH)2](1).The complex was pre-pared by hydrothermal reaction.A mixture of Tb(NO3)3‚6H2O(0.30 g,0.66mmol),succinic acid(H2Suc,0.12g,1mmol),benzoic acid (HBC,0.12g,1mmol),Ni(CH2COO)2(0.25g,1mmol),ethylenedi-amine(0.5mL),and H2O(15mL)was sealed into a bomb equipped with a Teflon liner,heated at150°C for4days,and then cooled at10°C/3h to100°C,followed by slow cooling to room temperature.Light yellow block crystals for1were obtained in ca.73.32%yield(based on Tb).Anal.Calcd for C23H19O10Tb2(773.24):C,35.67;H,2.44.*Corresponding author.E-mail:yhxing2000@.†Liaoning Normal University.‡Jilin Normal University.§Chinese Academy of Sciences.200710 2041204610.1021/cg070511y CCC:$37.00©2007American Chemical SocietyPublished on Web09/12/2007Found:C,35.69;H,2.46.IR data(KBr pellet,ν[cm-1]):3618,3586, 3429,3062,2927,2848,1613,1594,1546,1434,1306,1255,1162, 1074,1023,981,940,851,823,795,715,674,614,549,435,363, 322.Synthesis of[Eu2(Suc)0.5(BC)3(OH)2](2).The procedure was the same as that for1except that Tb(NO3)3‚6H2O was replaced by Eu-(NO3)3‚6H2O(0.30g,0.66mmol).Yield:80.27%(based on Eu).Anal. Calcd for C23H19O10Eu2(759.30):C,36.32;H,2.52.Found:C,36.35; H,2.50.IR data(KBr pellet,ν[cm-1]):3612,3591,3351,3062,2982, 2945,2922,1599,1550,1545,1431,1305,1215,1176,1070,1050, 1024,1001,975,950,907,878,852,810,716,687,651,572,433, 348,312.Synthesis of[Sm2(Suc)0.5(BC)3(OH)2](3).The procedure was the same as that for1except that Tb(NO3)3‚6H2O was replaced by Sm-(NO3)3‚6H2O(0.30g,0.66mmol).Yield:62.54%(based on Sm).Anal. Calcd for C23H19O10Sm2(756.08):C,36.47;H,2.53.Found:C,36.50; H,2.51.IR data(KBr pellet,ν[cm-1]):3610,3586,3426,3062,2853, 2927,1613,1594,1542,1431,1306,1255,1165,1065,1023,976, 940,851,823,795,717,670,628,600,544,498,432,401,358,303, 280,246.Synthesis of[Pr2(Suc)0.5(BC)3(OH)2](4).The procedure was the same as that for1except that Tb(NO3)3‚6H2O was replaced by Pr-(NO3)3‚6H2O(0.30g,0.66mmol).Yield:53.74%(based on Pr).Anal. Calcd for C23H19O10Pr2(737.20):C,37.41;H,2.81.Found:C,37.44; H,2.78.IR data(KBr pellet,ν[cm-1]):3604,3364,3062,2980,2926, 1597,1550,1546,1431,1416,1304,1214,1175,1070,1049,1024, 999,974,946,906,877,851,810,716,684,648,570,525,425,340.X-ray Crystallographic Determination.Suitable single crystals of four complexes were mounted on glass fibers for X-ray measurement. Reflection data were collected at room temperature on a Bruker AXS SMART APEX II CCD diffractometer with graphite monochromatized Mo K R radiation(λ)0.71073Å).Crystal structures were solved by the direct method.All non-hydrogen atoms were refined anisotropically. Hydrogen atoms were fixed at calculated positions and refined by usingTable1.Crystallographic Data for Complexes1-41234 formula C23H19O10Tb2C23H19O10Eu2C23H19O10Sm2C23H19O10Pr2 M(g mol-1)773.24759.30756.08737.20crystal system triclinic triclinic triclinic triclinicspace group P1h P1h P1h P1ha(Å) 6.759(2) 6.811(2) 6.8288(14) 6.9499(11)b(Å)12.008(4)12.062(4)12.087(2)12.2419(19)c(Å)16.140(5)16.063(5)16.046(3)15.891(3)R(deg)69.326(4)69.416(4)69.48(3)69.877(2)(deg)82.694(3)82.855(4)82.96(3)83.546(2)γ(deg)74.920(4)74.869(4)74.89(3)75.029(2)V(Å3)1182.5(6)1191.8(7)1196.9(4)1226.0(3)Z2222D calc 2.166 2.116 2.098 1.997crystal size(mm3)0.433×0.03×0.0240.021×0.029×0.4590.151×0.231×0.3410.017×0.032×0.312 F(000)738726722710µ(Mo K R)(mm-1) 5.987 5.270 4.913 3.981θ(deg) 1.90-29.04 2.64-28.99 3.09-27.48 1.89-29.05reflns collected73187458118557624independent reflns(I>2σ(I))5427548554265605params310316316316∆(F)(eÅ-3) 1.628and-2.245 2.967and-2.9050.821and-0.897 2.122and-2.771 goodness of fit 1.029 1.045 1.084 1.031R a0.0388(0.0506)b0.0528(0.0778)b0.0278(0.0384)b0.0448(0.0549)b wR2a0.0952(0.1032)b0.1321(0.1519)b0.0707(0.0747)b0.1260(0.1378)ba R)∑||F o|-|F c||/∑|F o|;wR2)[∑(w(F o2-F c2)2/[∑(w(F o2)2]1/2;[F o>4σ(F o)].b Based on all data.Table2.Selected Bond Lengths(Å)for Complex1aTb1-O4 2.332(4)Tb1-O8A 2.343(4)Tb1-O3B 2.369(4)Tb1-O8B 2.408(4)Tb1-O2A 2.414(4)Tb1-O3 2.450(4)Tb1-O10 2.484(4)Tb2-O1 2.471(5)Tb1-O6A 2.764(4)Tb2-O6 2.352(4)Tb2-O7 2.317(4)Tb2-O9 2.327(4)Tb2-O10 2.420(4)Tb2-O3 2.373(4)Tb2-O5 2.376(4)Tb1-O1A 2.650(5)Tb2-O8 2.463(4)a Symmetry transformations used to generate equivalent atoms:A x+1,y,z;B-x,-y+2,-z.Table3.Selected Bond Angles(deg)for Complex1aO4-Tb1-O8A81.08(15)O4-Tb1-O3B73.86(15)O8A-Tb1-O3B105.70(14) O4-Tb1-O8B126.98(14)O8A-Tb1-O8B71.33(16)O3B-Tb1-O8B71.53(14) O4-Tb1-O2A157.09(16)O8A-Tb1-O2A115.94(15)O3B-Tb1-O2A112.85(15) O8B-Tb1-O2A74.99(15)O4-Tb1-O391.62(15)O8A-Tb1-O3172.50(12) O3B-Tb1-O370.31(15)O8B-Tb1-O3112.36(14)O2A-Tb1-O371.55(14) O4-Tb1-O1076.10(15)O8A-Tb1-O1014.54(14)O3B-Tb1-O10124.30(14) O8B-Tb1-O10156.72(15)O2A-Tb1-O1082.56(15)O3-Tb1-O1064.85(13) O4-Tb1-O1A134.10(15)O8A-Tb1-O1A67.80(14)O3B-Tb1-O1A145.50(14) O8B-Tb1-O1A74.45(14)O2A-Tb1-O1A51.29(15)O3-Tb1-O1A119.17(13) O10-Tb1-O1A86.82(14)O4-Tb1-O6A76.07(15)O8A-Tb1-O6A66.00(13) O3B-Tb1-O6A149.75(15)O8B-Tb1-O6A126.72(13)O2A-Tb1-O6A96.26(15) O3-Tb1-O6A114.05(12)O10-Tb1-O6A49.23(13)O1A-Tb1-O6A60.98(14) O7-Tb2-O979.13(15)O7-Tb2-O696.08(16)O9-Tb2-O677.65(15) O7-Tb2-O3101.31(14)O9-Tb2-O3147.30(14)O6-Tb2-O3134.00(14) O7-Tb2-O5145.38(16)O9-Tb2-O578.09(15)O6-Tb2-O5104.07(16) O3-Tb2-O584.66(15)O7-Tb2-O1076.44(15)O9-Tb2-O1081.67(14) O6-Tb2-O10159.02(15)O3-Tb2-O1066.98(13)O5-Tb2-O1074.75(15) O7-Tb2-O8145.55(15)O9-Tb2-O826.14(14)O6-Tb2-O871.18(14) O3-Tb2-O870.50(13)O5-Tb2-O868.71(14)O10-Tb2-O8125.43(13) O7-Tb2-O176.52(15)O9-Tb2-O1136.17(15)O6-Tb2-O19.43(17) O3-Tb2-O173.79(14)O5-Tb2-O1136.92(15)O10-Tb2-O1125.98(15) O8-Tb2-O169.05(14)a Symmetry transformations used to generate equivalent atoms:A x+1,y,z;B-x,-y+2,-z.2042Crystal Growth&Design,Vol.7,No.10,2007Zhang et al.a riding mode.All calculations were performed using the SHELX-97program.15Crystal data and details of the data collection and the structure refinement are given in Table 1.Selected bond lengths and bond angles of complex 1are listed in Tables 2and 3,and selected bond lengths and bond angles of complexes 2-4are listed in Tables S1and S2of the Supporting Information,respectively.Results and DiscussionElemental analysis and thermogravimetric analyses studies performed on the complexes 1-4reveal that they are extremely similar in structure with slight differences.Here,complex 1is taken as an example to present and discuss the structure in detail.Crystal Structure of Complex 1.The structure of complex 1reveals that it is a two-dimensional framework,crystallizing in triclinic space group P 1h .An asymmetric unit [Tb 2(Suc)0.5-(BC)3(OH)2]contains one eight-coordinated and one nine-coordinated terbium ion,half a succinic acid,three benzoic acid ligands,and two hydroxyl groups.The coordination modes of the two terbium ions (Tb1and Tb2)are shown in Figure 1.Tb1is coordinated with nine oxygen atoms from one chelating bidentate carboxyl group (O1A and O2A)and one dimonoden-tate carboxyl group (O4)from benzoic acid,one chelating bidentate carboxyl group (O6A and O10)from succinic acid,and four coordination hydroxyl group molecules (O3,O3A,O8A,and O8B),as shown in Figure 1a.The eight oxygen atoms coordinated with Tb2are from four dimonodentate carboxyl groups (O1,O5,O7,and O9)from benzoic acid,two dimono-dentate carboxyl groups (O6and O10)from succinic acid,and two hydroxyl groups (O3and O8)(Figure 1b).The average distances of Tb -O BC (from benzoic acid),Tb -O Suc (from succinic acid),and Tb -O OH are 2.385(17),2.599(18),and 2.407-(15)Å,respectively.The average bonds of Tb -O BC are similar to those of other complexes,for example,[TbL 3(DMSO)-(H 2O)]2,[TbL 3(DMF)(H 2O)]2,and [TbL 3(Bpy)(H 2O)]2‚2H 2O](HL )p -aminobenzoic acid;62.388(3),2.392(3),and 2.367(4)Å,respectively).The average length of Tb -O Suc is longer than that of reported complexes,such as {[Tb 2(suc)3(H 2O)2]‚H 2O }n 13c (2.431(15)Å).The average distance of Tb -O OH (2.358(12)Å)is shorter than that of other similar complexes 13g due to the difference of ligands.Hydroxyl group as terminal ligand in lanthanide complexes is very common;however,the coordina-tion mode of µ3-OH 13g is rare like the title complexes.To deeply understand the structures for frameworks,it would be important to explore the connection modes of the metal centers and organic ligands.In the framework,lanthanide metalcenter atoms (Tb1,Tb2)and their corresponding centrosymmtric atoms link through benzoic acid ligands to form a 1D chain structure along the [010]direction.In the chain,there are two coordination modes for the benzoic acids:dimonodentate and chelating/bridging bidentate.Tb1and Tb2are linked by chelating/bridging bidentate and dimonodentate modes,respec-tively.And the two types of coordination modes of bezonic acid appear alternately (Figure 2).Tb1and Tb2ions and their corresponding centrosymmtric atoms are connected by µ3-OH to form anabsent-cubicFigure 1.Coordination environments of (a)Tb1and (b)Tb2in complex 1with non-hydrogen atoms drawn by diamond.Symmetry codes:A x +1,y ,z ;B -x ,-y +2,-z.Figure 2.One-dimensional chain structure formed Tb1,Tb2,and their corresponding centrosymmetric atoms and benzoic acid ligands on [101]plane for complex 1.Hydrogen atoms and coordination hydroxyl groups are omitted forclarity.Figure 3.(a)Absent-cube arrangement skeleton formed by µ3-OH and two Tb ions of 1,(b)two lanthanide metal center atoms (Tb1and Tb2)and their centrosymmetric atoms linked by carboxyl groups of succinic acid ligands and µ3-OH to lead to an infinite inorganic wall on [110]plane,and (c)infinite inorganic walls linked to each other by phenyl groups of benzoic acid ligands and the carbon atoms of the succinate anions.Hydrogen atoms and parts of benzoic acid are omitted for clarity.Two-Dimensional Metal -Organic Frameworks Crystal Growth &Design,Vol.7,No.10,20072043arrangement skeleton along the x -axis,as shown in Figure 3a.Crystallographically equivalent Tb2ions are linked by one dimonodentate carboxylate group of one succinic acid ligand to form an edge-sharing “...Tb -O -C -O-Tb...”chain.These special connection fashions of Tb ions lead to an infinite inorganic wall (Figure 3b).The inorganic walls are linked to each other through the carbon atoms of the succinate anions on the [110]plane and phenyl groups of the benzoic acid ligands on the [101]plane,leading to a two-dimensional open frame-work structure,as shown in Figure 3c.Carefully examining the structure of the complex,we find that the coordination mode of succinic acid ligands in complex 1is rare;that is,each of two carboxylate groups of succinic acid adopts a µ3-η2-η2-bridging (namely,one oxygen atom of the carboxylate group connects two metal ions,the other one connects also two metal ions,and the carboxylate group coordinates to three metal ions)coordination mode.The carboxylate of each benzoic acid between two inorganic walls adopts a µ2-η1-η1-bridging (namely,one oxygen atom of the carboxylate group connects one metal ion,the other one connects also one metal ion,and the carboxylate group coordinates to two metal ions)coordination mode.Along the [100]direction,these phenyl rings between two inorganic walls are parallel to each other,and the distance between rings is 6.731(15)Å(Figure 4).A two-direction packing structure of complex 1is formed as shown in Figure 5.Thermal Properties.The thermal stability of complexes in N 2was examined by the TG,DTG,and DTA techniques in the temperature range of 20-1000°C.Figure 6shows the TG -DTG -DTA curve for complex 1at a heating rate of 10°C/min under N 2atmosphere.The thermoanalytical data for complexes 1-4are listed in Table 4.As shown in Figure 6,the thermal decomposition process of complex 1can be divided into three stages.The first weight loss of 4.41%between 145and 361°C corresponds to the release of two coordination hydroxyl groups.The second weight loss of 7.54%was observed in the temperature range of 388-468°C,which is attributed to the release of 0.5succinic acid molecules (7.50%theoretical weight loss).In the third stage,in the range of 472-907°C,it experiences a 26.20%weight loss,which is attributed to therelease of one benzoic acid and two CO 2molecules (27.03%theoretical weight loss).According to the data of Table 4,it can be found that although the structures of complexes 1-4are similar,different metal ions coordinated to ligands have an impact on the courses of thermal decomposition of complexes.Photoluminescent Properties.The luminescent behaviors of complexes 1and 2were investigated in the solid state at room temperature.When excited at 285.5nm for 1and 396nm for 2,they emit green luminescence (1)and red light (2)at room temperature (Figure 7).The emission peaks of the complexes correspond to the transitions from 5D 4f 7F n (n )6,5,4,and 3)transitions at 490,544,583,and 621nm for the Tb(III)ion in 1and 5D 0f 7F n (n )1,2,3,and 4)transitions at 590,618,653,and 702nm for Eu (III)ion in 2.Among these emission lines,the most striking green luminescence (5D 4f 7F 5)for complex 1and red emissions (5D 0f 7F 2)for complex 2were observed in their emission spectra.IR Spectrum.As shown in Figure S2in the Supporting Information,the complexes 1and 3display similar IR spectral shape,while the IR spectral shapes of 2and 4are also similar.Both IR spectral shapes are slightly different.For complex 1,peaks appearing at 1434and 1613cm -1should be assigned to the symmetric and asymmetric stretching vibrations of the carboxylate groups.The bands of 1594and 1546cm -1are attributed to the aromatic skeleton vibration of the benzene ring.The νd C -H of benzene and the νC -C of the benzene ringhaveFigure 4.Structure view of parallel phenyl rings of benzoic acid between two inorganic walls along the [100]direction for complex 1.Figure 5.Packing structure along the [100]direction of complex 1.Figure 6.The TG -DTG -DTA curve of complex 1.Table 4.Thermal Decomposition Data for Complexes 1-4mass loss (%)stageDTG peak temp (°C)obsd calcd probable composition of removed groups1I 306.0 4.41 4.402hydroxyl groups II 433.07.547.480.5succinic acidIII 539.026.2026.251benzoic acid and 2CO 22I 176.0 4.53 4.482hydroxyl groups II 377.07.677.640.5succinic acid III 548.031.8331.872benzoic acid3I 85.0 4.48 4.502hydroxyl groups II 305.07.697.670.5succinic acidIII 533.027.6127.641benzoic acid and 2CO 24I 169 4.65 4.612hydroxyl groups II 46224.1724.280.5succinic acid and 1benzoic acid III8125.875.971CO 22044Crystal Growth &Design,Vol.7,No.10,2007Zhang et al.bands at 3062and 674-851cm -1,respectively.Peaks appearing in the spectral range from 1306to 981cm -1should be assigned to the substitutions of the benzene ring.The spectral range from 2848to 2927cm -1is characteristic of the νC -H vibration modes of -CH 2-groups within the carbon chain of succinic acid.The broad band at 3429cm -1belongs to the typical band of hydroxyl group.The detailed attribution of IR for complexes 2-4is listed in Table 5.ConclusionsFour two-dimensional lanthanide coordination polymers with similar architectures,complexes 1-4,have been synthesized for the first time under hydrothermal conditions.X-ray diffrac-tion analyses reveal that they exhibit the same two-dimensional (2D)architecture and crystallized in triclinic space group P 1h for complexes 1-4.Infinite inorganic walls are formed by lanthanide ions,µ3-OH,and an edge-sharing “...Ln -O -C -O -Ln...”chain,which link to each other through the carbon atoms of the succinate anions on the [110]plane and phenyl groups of the benzoic acid ligands on the [101]plane,leading to a two-dimensional open framework structure.The thermogravi-metric analysis of 1-4and photoluminescent properties of complexes 1and 2were discussed.Different metal ions coordinated to the ligands have an impact on the courses of thermal decomposition of complexes,so the course of thermal decomposition of complexes is appreciably plexes 1and 2emit green and red luminescence at room temperature,respectively,and they could be anticipated as potential fluo-rescent materials.Acknowledgment.We wish to express our sincere thanks to National Natural Science Foundation of China (Grant No.20571036),SRF for ROCS,SEM,and Education Foundation of Liaoning Province in China (Grant 05L212)for financial assistance.Supporting Information Available:Tables listing selected bond lengths and bond angles and figures showing coordination environments of the Ln,chain structure,skeleton structure,view of the parallel phenyl rings,packing structure,and TG -DTG -DTA curves of complexes 2-4and IR spectra for compounds 1-4.This material is available free of charge via the Internet at .Tables of atomic coordinates,isotropic thermal parameters,and complete bond dis-tances and angles have been deposited with the Cambridge Crystal-lographic Data Center.Copies of this information may be obtained free of charge,by quoting the publication citation and deposition numbers CCDC 644782(1),644783(2),644781(3),and 644784(4),from the Director,CCDC,12Union Road,Cambridge,CB21EZ,UK (fax +44-1223-336033;e-mail deposit@;).References(1)(a)Seo,J.S.;Whang,D.;Lee,H.;Jun,S.I.;Oh,J.;Jeon,Y.J.;Kim,K.Nature 2000,404,982.(b)Chem,B.;Eddaoudi,M.;Hyde,S.T.;O’Keeffe,M.;Yaghi,O.M.Science 2001,291,1021.(c)Sato,O.;Iyoda,T.;Fujishima,A.;Hashimoto,K.Science 1996,271,49.(d)Kahn,O.;Martinez,C.Science 1998,279,44.(2)(a)Devic,T.;Serre,C.;Audebrand,N.;Marrot,J.;Fe ´rey,G.J.Am.Chem.Soc.2005,127,12788.(b)Lin,W.;Evans,O.R.;Xiong,R.;Wang,Z.J.Am.Chem.Soc.1998,120,13272.(c)Fang,Q.;Zhu,G.;Xue,M.;Sun,J.;Wei,Y.;Qiu,S.;Xu,R.Angew.Chem.,Int.Ed.2005,44,2.(d)Eddaoudi,M.;O’Keeffe,M.;Yaghi,O.M.Nature 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金属有机框架类新型铁肥的研制

第42卷第6期2023年 11月Vol.42 No.6Nov. 2023，73~79华中农业大学学报Journal of Huazhong Agricultural University金属有机框架类新型铁肥的研制吴珂1，2，周健民1，杜昌文1，31.中国科学院南京土壤研究所/土壤与农业可持续发展全国重点实验室，南京210008；2.江苏开放大学环境生态学院，南京 210017；3.中国科学院大学现代农业科学学院，北京 100049摘要为探索和评估Fe-MOF材料应用于铁肥的潜力，应用铁离子在温和的水热条件下合成铁基MOF （Fe-MOF）类新型铁肥，采用粉末X射线衍射（PXRD）、中红外光谱（FTIR-ATR）、X射线光电子能谱（XPS）以及扫描电子显微镜（SEM）等技术手段表征Fe-MOF 的元素组成和结构特征，利用静水溶出和土壤培养试验探究其养分释放行为。

结果显示，Fe-MOF由铁、氮、磷、碳、氧以及氢元素组成，其中铁的负载量达19.7%，三价铁和二价铁的物质的量比为1︰1，氮和磷的负载量分别为5.1%和14.7%；Fe-MOF在水溶液中84 d铁的累积释放率为4.7%，相应的在土壤中铁的累积释放率达到58.7%，呈现出优异的缓控释特征。

研究表明，以环境友好型材料为底物，通过简便绿色的水热合成工艺，实现了微量元素（铁）和大量元素（氮、磷）的协同配伍和定向组装，为新型铁肥的研发提供了新途径。

关键词铁基金属有机框架；水热合成；分子设计；铁肥；多元复合中图分类号S511；S143.1；TP39 文献标识码 A 文章编号1000-2421（2023）06-0073-07铁是自然界中存在的一种重要元素，在植物的生长和代谢中发挥着重要作用，如DNA合成、光合作用和呼吸作用等。

此外，铁还作为许多酶（包括细胞色素氧化酶、过氧化氢酶和过氧化物酶等）的原生基团激活许多代谢途径。

缺铁是许多作物中常见的微量元素失调症，这种现象在钙质和pH较高的土壤中更为明显，导致铁成为植物生长和新陈代谢的最大限制性营养元素之一［1-2］。

溶剂热法合成用于高效光催化燃油脱氮的TiO2@MIL-101(Cr)复合材料

DOI: 10.1016/S1872-5813(21)60170-6Solvothermal synthesis of TiO 2@MIL-101(Cr) for efficientphotocatalytic fuel denitrificationLU Yi 1,2，LIANG Ruo-wen 1,2,3，YAN Gui-yang 1，LIANG Zhi-yu 1,3，HU Wei-neng 2，XIA Yu-zhou 1 ，HUANG Ren-kun1,2,3,*（1. Province University Key Laboratory of Green Energy and Environment Catalysis , Ningde Normal University , Ningde 352100, China ；2. State Key Laboratory of Photocatalysis on Energy and Environment , Fuzhou University , Fuzhou 350002,China ；3. Fujian Provincial Key Laboratory of Featured Materials in Biochemical Industry ,Ningde Normal University , Ningde 352100, China ）Abstract: Solvothermal synthesis technique is an effective method to create composite materials. In this paper, a series of TiO 2@MIL-101(Cr) were prepared by the solvothermal method for photocatalytic denitrification of pyridine in fuel under visible light irradiation. The products were characterized by XRD, FT-IR, SEM, TEM, BET, DRS and ESR. The result shows that 20%TiO 2@MIL-101(Cr) has high catalytic activity, the pyridine removal efficiency reaches values as high as 70% after irradiation for 240 min. Finally, we obtained the possible mechanism of photocatalytic denitrification according to the HPLC-MS spectrometry results analysis.Key words: photocatalytic ；fuel ；denitrification ；MIL-101(Cr)；TiO 2CLC number: O643.32 Document code: ACrude gasoline is a necessity for human survival.And with the improvement of oil exploitationtechnology [1], more oil can be exploited and used.However, there are many kinds of nitrogen-containing compounds (NCCs) in fuel, such as pyridinederivatives and pyrrole derivatives [2−4]. These NCCs will be released into the atmosphere in the form ofnitrogen oxides by burning [5]. It will seriously damageour air environment and our health [6]. Therefore, the selective removal of NCCs from crude gasoline has become a global research hotspot.Metal organic frameworks (MOFs) are classes of organic coordination polymer materials, which are regarded as an important class of materials due to their controllable structure, pore size and high specificsurface area [7−9]. Because of its unique structural characteristics, MOFs show excellent performance in various adsorption based applications, such as gassensing materials [10−12], gas storage materials [13−15],catalytic materials [16−18], etc. For example, MIL-101(Cr)has strong adsorption performance [19], but the efficiency of catalytic fuel denitrification is relatively low. TiO 2, a class of photocatalyst in semiconductor material, has excellent photoelectric and photocatalytic properties.However, it only responds to UV and it can't efficientlyutilize solar light [20,21]. While MOFs often have responded in visible light. Therefore, the combination of TiO 2 and MOFs to form composite materials may enhance the response to visible light and improve its catalyticperformance [22]. It provides a promising method for selectively removing NCCs from crude gasoline.In this work, TiO 2@MIL-101(Cr) was successfully synthesized by a simple method. The structure and properties were characterized by XRD,SEM, TEM, FT-IR, UV-vis, DRS and BET. The performance of photocatalytic fuel denitrification was tested by simulating fuel (pyridine/n -octane).1 Experimental1.1 MaterialsChromium(Ⅲ) nitrate nonahydrate (Cr(NO 3)·9H 2O), terephthalic acid, hydrofluoric acid (HF), N , N -dimethylformamide (DMF) and tetrabutyl titanate were supplied by Aladdin Reagent Co., Ltd. All chemicals are of analytical grade and used as received. Deionized water was used in all experiments.1.2 Fabrication of MIL-101(Cr)In a typical experiment, 1.2 g of Cr(NO 3)·9H 2O,Received ：2021-08-04；Revised ：2021-09-23*Corresponding author. Tel: +86-593-2965018, E-mail: **************.cn.The project was supported by Program for Innovative Research Team in Science and Technology in Fujian Province University, Natural Science Foundation of Fujian Province (2019J05121), Research Project of Ningde Normal University (2019T03) and the Training Program Foundation for Distinguished Young Scholar by Fujian Province.本文的英文电子版由 Elsevier 出版社在 ScienceDirect 上出版 (/science/journal/18725813)第 50 卷第 4 期燃料化学学报Vol. 50 No. 42022 年 4 月Journal of Fuel Chemistry and TechnologyApr. 20220.5 g of terephthalic acid were dissolved in 15 mL deionized water to obtain a homogeneous solution. The mixture was transferred into a Teflon-lined stainless-steel autoclave and heated at 220 °C for 8 h. The precipitate A was collected by centrifugation, then washed with ethanol for 3 times. The precipitate washed with hot DMF and hot ethanol several times, respectively. The MIL-101(Cr) was collected by a centrifugation and washed three times with ethanol, and then dried at 65 °C for 8 h.1.3 Fabrication of TiO2Specifically, 1 mL tetrabutyl titanate was added into 40 mL of ethanol under stirring for 30 min, then the resulting mixture was transferred into a Teflon-lined stainless-steel autoclave and heated at 220 °C for 3 h. The TiO2 was obtained by centrifugation, after which it was washed several times with ethanol and deionized water. The obtained white powder was dried at 65 °C for 8 h.1.4 Fabrication of TiO2@MIL-101(Cr)For preparation of 5%TiO2@MIL-101(Cr), 54.3 mg tetrabutyl titanate and 250 mg MIL-101(Cr) was added into 40 mL of ethanol under stirring for30 min, then the resulting mixture was transferred intoa Teflon-lined stainless-steel autoclave and heated at 220 °C for 3 h. The 5%TiO2@MIL-101(Cr) material was collected by a centrifugation and washed three times with ethanol, then dried at 65 °C for 8 h. x%TiO2@MIL-101(Cr) with other TiO2 ratios (x is the mass ratio of TiO2) were synthesized by similar methods.1.5 CharacterizationsX-ray diffraction (XRD) patterns were obtained using a Bruker D8 Advance X-ray diffractometer. Fourier-transform infrared reflectance (FT-IR) spectra were measured using a Shimadzu IRPRESTIGE-21 spectrophotometer. Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) images were obtained using a FEI Talos F200X instrument. Ultraviolet-visible diffuse reflectance spectra (UV-vis DRS) were obtained using a Shimadzu UV-2700 UV-vis spectrophotometer. The Brunauer-Emmett-Teller (BET) surface areas of the samples were measured using an ASAP 2460 apparatus. X-ray photoelectron spectroscopy (XPS) measurements were performed using a Thermo Scientific ESCA Lab 250 spectrometer.1.6 Photocatalytic performanceFirst, 70 mg of pyridine was dissolved in 1.0 L octane to prepare 100 μg/g simulated NCCs-containing gasoline fuel. Second, 50 mg photocatalyst and 50 mL pyridine/octane solution (100 μg/g) were put into a quartz reactor with magnetic stirring, and then the suspension was stirred in the dark for 4 h to ensure the adsorption-desorption equilibrium was reached. Third, the suspensions were irradiated using a 300 W Xe lamp (PLS-SXE 300), which equipped with a UV-cut filter to cut off light of wavelength shorter than 420 nm. Last, 1.5 mL of the sample was centrifuged at intervals. At selected time intervals, aliquots of the suspension were removed and centrifuged. The residual concentration of pyridine in the supernatant was monitored using a Varian Cary 60 spectrometer.2 Results and discussion2.1 Characteristics of the prepared catalystsAs illustrated in Figure 1, X-ray diffraction pattern of TiO2, MIL-101(Cr), x%TiO2@MIL-101(Cr) composites were investigated in the scanning range 5° < 2θ < 80°. It can be observed that the typical peaks of MIL-101(Cr) corresponded to the simulated MIL-101(Cr), suggesting the successful preparation of the MIL-101(Cr). After incorporation of TiO2, the position and relative intensity of main diffraction peaks can be indexed to the MIL-101(Cr), which indicate that the crystalline structure of MIL-101(Cr) is retained. What’s more, the typical peaks at 25.3°, 37.8°, 48°, 53.9°, 55.1°, 62.7° and 68.8° correspond to the (101), (004), (200), (105), (211), (204) and (116) planes of anatase TiO2 (JCPDS no.21-1272), respectively. The results indicate that the successful preparation of TiO2@MIL-101(Cr) composites. Interestingly, the characterization peaks of TiO2 in 5%TiO2@MIL-101(Cr) composite is not obvious, which suggest some TiO2 grow in cages while a small amount of TiO2 cover on the surface of MIL-101(Cr) when the mass ratio is small. In addition, with the mass ratio of TiO2 increase, the relative intensity of TiO2 are enhanced on the surface of MIL-101(Cr).The SEM images in Figure 2(a)−2(e) reveal the morphologies of MIL-101(Cr) and x%TiO2@MIL-101(Cr) (x=5, 10, 20, 50). As shown in Figure 2(a), the synthesized MIL-101(Cr) has a uniform octahedral morphology. As shown in Figure 2(b)-2(e), the number and density of the particles increase on the surface with increasing x%. It can be seen that the particles are well dispersed. In addition, the change of the amount of TiO2 added to the composite has no obvious effect on第 4 期LU Yi et al.：Solvothermal synthesis of TiO2@MIL-101(Cr) for efficient photocatalytic fuel denitrification 457the morphology of the composite.The TEM image (Figure 3 (a)) clearly identify some of the black particles, which indicate TiO 2nanoparticles are tightly wrapped around the surface of MIL-101(Cr). 20%TiO 2@MIL-101(Cr) still shows octahedral morphology, indicating that the introduction of TiO 2 has no significant effect on the morphology of MIL-101(Cr). As shown in Figure 3(b), the lattice fringe with a lattice spacing of 0.33 nm can correspond to the (101) plane of anatase TiO 2. According to elemental analysis in Figure 3(d)−3(f), C, Cr, Ti are uniformed dispersed in octahedron, indicating TiO 2 is uniformly dispersed on the surface and inside of the MIL-101(Cr).10203040502θ /(°)50%TiO 2@MIL-101 (Cr)40%TiO 2@MIL-101 (Cr)30%TiO 2@MIL-101 (Cr)20%TiO 2@MIL-101 (Cr)10%TiO 2@MIL-101 (Cr)5%TiO 2@MIL-101 (Cr)TiO 2Simulated MIL-101 (Cr)Pdf#21-1272MIL-101 (Cr)I n t e n s i t y /(a .u .)607080Figure 1 XRD patterns of TiO 2@MIL-101(Cr),MIL-101(Cr) and TiO 2400 nm 400 nm 400 nm400 nm400 nm Figure 2 SEM images of (a) MIL-101(Cr), (b) 5%MIL-101(Cr), (c) 10%MIL-101(Cr)(d) 20%MIL-101(Cr) and (e) 50%MIL-101(Cr)200 nm200 nm 200 nm 200 nm5 nm2 nm0.33 nm (101)Figure 3 (a) TEM of 20%TiO 2@MIL-101(Cr), ((b), (c)) HRTEM of 20%TiO 2@MIL-101(Cr), (d) C, (e) Cr, (f) TiFigure 4(a) shows the FT-IR spectroscopy images for MIL-101(Cr) and 20%TiO 2@MIL-101(Cr). The absorption bands at approximately 1619 and 1396 cm −1in the spectrum of H 2BDC could be attributed to the O−C−O asymmetrical stretching vibration and symmetrical stretching vibration,458燃料化学学报第 50 卷respectively. It shows that the material containsdicarboxylate group. The band at 1015 and 748 cm −1are attributed to the C−H of benzene ring. And theband at 663 cm −1is attributed to Cr−O vibration mode.40003433(a)MIL-101 (Cr)161913961015748587350030002500Wavenumbers /cm −1T r a n s m i t t a n c e /%200015001000500(b)MIL-101 (Cr)TiO 2@MIL-101 (Cr)3433161913961015748587T r a n s m i t t a n c e /%4000350030002500Wavenumbers /cm −1200015001000500Figure 4 (a) FT-IR spectra of MIL-101(Cr) and (b) comparison FT-IR spectra of MIL-101(Cr) and 20%TiO 2@MIL-101(Cr)In order to determine whether the structure of MIL-101(Cr) was destroyed after incorporation of TiO 2, FT-IR spectra of MIL-101(Cr) and20%TiO 2@MIL-101(Cr) are shown in Figure 4(b). In the 20%TiO 2@MIL-101(Cr), the typical absorption peaks of MIL-101(Cr) still exist, which indicate that the structure of MIL-101(Cr) is not damaged after incorporation of TiO 2.A b s o r b e d v o l u m e /(c m 3·g −1)Relative pressurel p /p 0Figure 5 N 2 adsorption/desorption isotherms curves of MIL-101(Cr) and x %TiO 2@MIL-101(Cr) (x =5, 10, 20, 50)The N 2 adsorption/desorption isotherms curves of MIL-101(Cr) and x %TiO 2@MIL-101(Cr) (x =5, 10, 20,50) are shown in Figure 5. As shown in Table 1, the BET surface area and pore volume of MIL-101(Cr) aredetermined to be approximately 3341.1767 m 2/g and1.63 cm 3/g, respectively. As the mass ratio of TiO 2increase, the BET surface areas and pore volumes of x %TiO 2@MIL-101(Cr) (x =5, 10, 20, 50) decrease significantly. This is because the crystalline TiO 2 grow in the channel or the surface. Although the addition of TiO 2 contributes to the improvement of catalytic activity, the low specific surface area may limit the catalytic efficiency. Therefore, it is necessary to find the optimal TiO 2 addition amount.Table 1 BET surface Area, pore volume of TiO 2@MIL-101(Cr) compositesSample BTE surface area/(m 2·g −1)Pore volume/(cm 3·g −1)MIL-101(Cr)3341.1767 1.635%TiO 2@MIL-101(Cr)2855.3102 1.4910%TiO 2@MIL-101(Cr)2585.1894 1.3720%TiO 2@MIL-101(Cr)2325.2452 1.2350%TiO 2@MIL-101(Cr)1742.24490.99Figure 6(a) shows the UV-vis spectra of x %TiO 2@MIL-101(Cr), MIL-101(Cr) and TiO 2. TiO 2shows an absorption edge about 400 nm. Based on the Kubelka-Munk function, the band gaps can becalculated. Obviously, the band gap of MIL-101(Cr) is about 2.42 eV. As showed in Figure 6(b), the band gaps of 20%TiO 2@MIL-101(Cr) and 50%TiO 2@MIL-101(Cr) are 2.37 and 2.40 eV, respectively. The band第 4 期LU Yi et al.：Solvothermal synthesis of TiO 2@MIL-101(Cr) for efficient photocatalytic fuel denitrification459gaps of the MIL-101(Cr) composite materials decrease after incorporation of TiO2, which may promote the separation of photoinduced electron-hole pairs.(a)300400Wavelength /nmAbsorbance/(a.u.)50060070080050%TiO2@MIL-101 (Cr)20%TiO2@MIL-101 (Cr)TiO2MIL-101 (Cr)(b)2.3246810122.4hv /eVhv /eV2.42TiO2: 3.252.372.40(Ahv)2(Ahv)22.5 2.62.53.0 3.54.02.7 2.850%TiO2@MIL-101 (Cr)20%TiO2@MIL-101 (Cr)TiO2MIL-101 (Cr)Figure 6 (a) UV-vis DRS spectra of TiO2 and x%TiO2@MIL-101(Cr) composites and (b) (Ahν)2 vs hν of (a )MIL-101 (Cr), (b)20%TiO2@MIL-101 (Cr) and (c) 50%TiO2@MIL-101 (Cr)2.2 Photocatalytic performanceThe photocatalytic activities of MIL-101(Cr) andx%MIL-101(Cr) for the denitrogenation of NCCs havebeen evaluated using visible light (λ ≥ 420 nm). Asillustrated in Figure 7(a), 20%TiO2@MIL-101(Cr) hashigh active of catalysis (70%) within 4 h, while MIL-101(Cr) and TiO2 show no activity for thedenitrogenation. To further understand the effect ofTiO2 for the photocatalytic activity of TiO2@MIL-101(Cr) composites, x%TiO2@MIL-101(Cr) (x=5, 10,20, 30, 40, 50) were tested by photocatalyticdenitrogenation. The results show that 20%TiO2@MIL-101(Cr) has optimal active of catalysis. The reason forthis phenomenon is considered that suitable proportionof TiO2 and MIL-101(Cr) promote photocarriers (holesand electrons) generation. The catalytically active sitesof composites are enclosed with the increasing of TiO2,which will lead to reduction in denitrogenation.102030Degradationrate/%4050607012Time /hMIL-101 (Cr)-lightMIL-101 (Cr)-blackTiO2-lightTiO2-black20%TiO2MIL-101 (Cr)-light20%TiO2MIL-101 (Cr)-black(a)34102030Degradationrate/%405060705%TiO2MIL-101 (Cr)10%TiO2MIL-101 (Cr)20%TiO2MIL-101 (Cr)30%TiO2MIL-101 (Cr)40%TiO2MIL-101 (Cr)50%TiO2MIL-101 (Cr)(b)012Time /h34Figure 7 (a) Photocatalytic denitrogenation of pyridine overMIL-101(Cr), TiO2 and 20%TiO2@MIL-101(Cr) under visiblelight and black, (b) photocatalytic denitrogenation of pyridine atdifferent content of TiO22.3 Photocatalytic mechanismThe generation and migration of photogeneratedcarriers under light irradiation was studied byphotoelectric chemistry experiment. As shown inFigure 8(a), the photocurrent intensity of 20%TiO2@MIL-101(Cr) is higher than MIL-101(Cr), indicatingthat the lifetime of photogenerated electron-hole pairsof 20%TiO2@MIL-101(Cr) is higher than MIL-101(Cr). Moreover, to better understand the excellentcharge carrier transmission performance of 20%TiO2@MIL-101(Cr), EIS Nyquist plots was obtained.Compared with MIL-101(Cr) and 20%TiO2@MIL-101(Cr), the semicircle of 20%TiO2@MIL-101(Cr) issmaller, which indicate the significantly increasedcharge-carrier transfer of 20%TiO2@MIL-101(Cr)compared with MIL-101(Cr) (Figure 8(b)). This resultis in good agreement with the photocurrent response,indicating that the addition of TiO2 can effectivelyimprove the separation of charge and carrier.The HPLC-MS spectrometry results are displayedin Figure 9. After 4 h irradiation, the peak intensity of 460 燃料化学学报第 50 卷pyridine at approximately m/z = 79.04 is greatly decreased, which implying that the denitrogenation of pyridine is successful. In addition, two new peaks at 46.03, 85.04 gradually appears, indicating that pyridine has been transformed into C 4H 4O 2 and CH 3NH 2, which are the protonated intermediate products. The most reliable and direct method for investigating reactive species is ESR. In the presence of 20% TiO 2@MIL-101(Cr), it is difficult to detect the signal of DMPO-·O2even after 5 min of irradiation, implying that ·O 2is not the main active species during this reaction (Figure 10(a)). The characteristic quartet peaks of the DMPO-·OH adduct can be easily detected after visible light irradiation for 5 min (Figure 10(b)), indicating that ·OH radicals have been generated. As illustrated in Figure 10(b), the ESR signal of TEMPO decreased,confirming the production of photogenerated holes.Furthermore, as shown in Figure 11, the possible denitrogenation pathway of pyridine are consistent with the information reported in one of our previouslypublished papers [23−25].1.4(a)MIL-101 (Cr)20%TiO 2@MIL-101 (Cr)1.21.00.80.60.40.20150200Irradiation time /sP h o t o c u r r e n t /(μA ·c m −2)250300(b)MIL-101 (Cr)20%TiO 2@MIL-101 (Cr)25201510−Z ″ /(103 Ω)Z ′ /(103Ω)502520151050Figure 8 (a) Transient photocurrent responses of MIL-101(Cr) and 20%TiO 2@MIL-101(Cr), (b) Nyquist impedance plots ofMIL-101(Cr) and 20%TiO 2@MIL-101(Cr)45.0349.9259.0861.0464.0769.0270.9375.0479.0481.0083.0887.0393.0395.0697.01101.1440(a)35303035404550556065m /z7075808590951002520151050(b)m /z051035.3342.1945.0446.0353.1064.1167.0169.0471.0675.1078.0381.0383.1085.0486.9793.0599.0479.0455.3359.09Figure 9 High-performance liquid chromatography profiles of pyridine after different irradiation times: (a) 0 h and (b) 4 h3460(a)34803500Magnetic field /mTDMPO-·O 2−T i me /mi nI n t e n s i t y /(a r b . u n i t s )3520053540(b)DMPO-·OHI n t e n s i t y /(a r b . u n i t s )T i me /mi n5346034803500Magnetic field /mT35203540(c)Tempot-h +I n t e n s i t y /(a r b . u n i t s )T i m e /mi n5346034803500Magnetic field /mT35203540Figure 10 Electron spin response spectra of various radical adducts第 4 期LU Yi et al.：Solvothermal synthesis of TiO 2@MIL-101(Cr) for efficient photocatalytic fuel denitrification461Nh +N +NHH H +e +H 2O O 2CO 2+H 2O NH 3+HCOOH+CHO−NH 2O 2OHNNH H OH OHCHO CHO CHOCHOFigure 11 Possible denitrogenation pathway of pyridine3 ConclusionsSolvothermal synthesis of the MIL-101(Cr) hashigh surface area (3341.1767 m 2/g) and pore volume(1.63 cm 3/g). The results show that the photodenitrogenation performance of MIL-101(Cr)increase greatly owning to composite with TiO 2.20%TiO 2@MIL-101(Cr) has the highest catalytic activity, and the denitrogenation ratio can reach 70%within 4 h under visible light. The excellent photocatalytic performance can be attributed to the introduction of inorganic semiconductor TiO 2 into MIL-101 (Cr), which increases the generation and mobility of photocarriers. This work provides a new perspective for the realization of efficient photocatalytic performance.ReferencesYIN C. International law regulation of offshore oil and gas exploitation [J ]. Environ Impact Assess Rev ，2021，88：106551.[1]PRADO G H C, RAO Y, KLERK A. Nitrogen removal from oil: A review [J ]. Energy Fuels ，2016，31（1）：14−36.[2]BHADRA B N, BAEK Y S, CHOI C H, JHUNG S H. How neutral nitrogen-containing compounds are oxidized in oxidative-denitrogenation ofliquid fuel with TiO 2@carbon [J ]. 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J Nano Res ，2017，11（2）：1109−1123.[17]WANG C-C, DU X-D, LI J, GUO X-X, WANG P, ZHANG J. Photocatalytic Cr(VI) reduction in metal-organic frameworks: A mini-review [J ].App Catal B: Environ ，2016，193：198−216.[18]KHAN N A, JHUNG S H. Phytic acid-encapsulated MIL-101(Cr): Remarkable adsorbent for the removal of both neutral indole and basicquinoline from model liquid fuel [J ]. Chem Eng J ，2019，375.[19]GUO Q, ZHOU C, MA Z, YANG X. Fundamentals of TiO 2 photocatalysis: Concepts, mechanisms, and challenges [J ]. Adv Mater ，2019，31（50）：[20] 462燃料化学学报第 50 卷第 4 期LU Yi et al.：Solvothermal synthesis of TiO2@MIL-101(Cr) for efficient photocatalytic fuel denitrification 4631901997.[21]FUJIMOTO T M, PONCZEK M, ROCHETTO U L, LANDERS R, TOMAZ E. Photocatalytic oxidation of selected gas-phase VOCs using UV light, TiO2, and TiO2/Pd[J]. Environ Sci Pollut Res Int，2017，24（7）：6390−6396.[22]LIN J Y, LEE J, WEN D O, KWON E, LIN K. Hierarchical zif-decorated nanoflower-covered 3-dimensional foam for enhanced catalytic reduction of nitrogen-containing contaminants[J]. J Colloid Interface Sci 2021, 602: 95-104.[23]HU W, YAN G, LIANG R, JIANG M, HUANG R, XIA Y, CHEN L, LU Y. Construction of a novel step-scheme CdS/Pt/Bi2MoO6 photocatalyst for efficient photocatalytic fuel denitrification[J]. RSC Adv，2021，11（38）：23288−23300.[24]LIANG R, LIANG I, CHEN F, XIE P, WV Y, WANG X, YAN G, WV L. Sodium dodecyl sulfate-decorated MOF-derived porous Fe2O3 nanoparticles: High performance, recyclable photocatalysts for fuel denitrification[J]. Chin J Catal，2020，41（1）：188−199.[25]HUANG R, LIANG R, FAN H, YING S, WU L, WANG X, YAN G. Enhanced Photocatalytic fuel denitrification over TiO2/alpha-Fe2O3 nanocomposites under visible light irradiation[J]. Sci Rep，2017，7（1）：7858.溶剂热法合成用于高效光催化燃油脱氮的TiO2@MIL-101(Cr)复合材料卢　沂1,2 ，梁若雯1,2,3 ，颜桂炀1 ，梁志喻1,3 ，胡未能2 ，夏宇宙1 ，黄仁昆1,2,3,*（1. 宁德师范学院福建省绿色能源与环境催化高校重点实验室福建宁德，352100；2. 福州大学能源与环境光催化国家重点实验室，福建福州，350002；3. 宁德师范学院福建省特色生物化工材料重点实验室福建宁德，352100）摘　要：溶剂热合成技术是一种有效合成复合材料的技术。

MOFs材料的应用研究进展

Open Journal of Natural Science 自然科学, 2020, 8(6), 547-551Published Online November 2020 in Hans. /journal/ojnshttps:///10.12677/ojns.2020.86064MOFs材料的应用研究进展孙亮1，王冬晶2*，郎晨瑜1，刘文宝1*，刘彬11辽宁大学药学院，辽宁沈阳2北京利龄恒泰药业有限公司，北京收稿日期：2020年10月16日；录用日期：2020年10月30日；发布日期：2020年11月6日摘要金属有机骨架(Metal-organic frameworks, MOFs)材料是一种新型的纳米多孔材料，近年来，MOFs材料由于其比表面积大，可设计性能强，较大的负载能力而被应用于各个学科，包括分析化学、药物分析、物理化学等学科。

MOFs材料能够应用于光催化、化学传感器、载药、荧光探针等领域，有着一个较好的发展前景。

关键词MOFs材料，应用，进展Application Research Progress of MOFsMaterialsLiang Sun1, Dongjing Wang2*, Chenyu Lang1, Wenbao Liu1*, Bin Liu11College of Pharmacy, Liaoning University, Shenyang Liaoning2Beijing Liling Hengtai Pharmaceutical Co. Ltd., BeijingReceived: Oct. 16th, 2020; accepted: Oct. 30th, 2020; published: Nov. 6th, 2020AbstractMetal-organic frameworks (MOFs) materials are a new type of nanoporous materials. In recent years, MOFs materials have been applied to various disciplines due to their large specific surface area, strong design performance, and large load capacity, including analytical chemistry, pharma-*通讯作者。

金属有机框架材料作为药物载体的研究进展

金属－有机框架材料作为药物载体的研究进展罗小莉胡德辉朱陈斌（广西中医药大学，广西南宁530200）【摘要】金属－有机框架（metal-organic frameworks，简称MOFs）材料因其独特的结构，在性能研究上备受研究人员的青睐，尤其在药物负载与控释方面因具有潜在应用价值而吸引人们的关注。

与传统的药物载体相比，金属-有机框架材料作为药物载体具有诸多优点，例如稳定性好、疗效佳、靶向性强、毒副反应小、合成简单等等，因此在临床医学方面具有很大的应用前景。

文章就金属-有机框架材料作为药物载体及其载药性能的研究做一综述，为其作为药物载体深入研究提供理论参考。

【关键词】金属－有机框架；药物；载体；综述【中图分类号】TQ46【文献标识码】A【文章编号】1008-1151(2019)01-0009-03 Research Progress of Metal-organic Frameworks as Drug Carriers Abstract: Metal-organic framework (MOFs) materials are favored by scientists for their unique structure, especially for their potential application value in drug loading and controlled release. Compared with traditional drug carriers, MOFs materials have many advantages, such as better stability, better curative effect, stronger targeting, smaller toxic and side effects and easier synthesis, etc. Therefore, they have great application prospect in clinical medicine. This paper reviews the research progress of MOFs materials as drug carriers and their drug carrying properties, which provides theoretical reference for the further research of MOFs that are as drug carriers.Key words: metal-organic frameworks; drug; carriers; review将金属－有机框架材料作为药物载体的研究已经成为当前科学界研究的热点。

The chemistry and applications of metal organic framworks

DOI: 10.1126/science.1230444, (2013);341 Science et al.Hiroyasu Furukawa The Chemistry and Applications of Metal-Organic FrameworksThis copy is for your personal, non-commercial use only.clicking here.colleagues, clients, or customers by , you can order high-quality copies for your If you wish to distribute this article to othershere.following the guidelines can be obtained by Permission to republish or repurpose articles or portions of articles): May 10, 2014 (this information is current as of The following resources related to this article are available online at/content/341/6149/1230444.full.html version of this article at:including high-resolution figures, can be found in the online Updated information and services, /content/suppl/2013/08/29/341.6149.1230444.DC1.html can be found at:Supporting Online Material /content/341/6149/1230444.full.html#ref-list-1, 13 of which can be accessed free:cites 358 articles This article /content/341/6149/1230444.full.html#related-urls 2 articles hosted by HighWire Press; see:cited by This article has been/cgi/collection/chemistry Chemistrysubject collections:This article appears in the following registered trademark of AAAS.is a Science 2013 by the American Association for the Advancement of Science; all rights reserved. The title Copyright American Association for the Advancement of Science, 1200 New York Avenue NW, Washington, DC 20005. (print ISSN 0036-8075; online ISSN 1095-9203) is published weekly, except the last week in December, by the Science o n M a y 10, 2014w w w .s c i e n c e m a g .o r g D o w n l o a d e d f r o m/10.1126/science.1230444Cite this article as H. FurukawaScienceDOI: 10.1126/science.1230444 liations is available in the full article online.*Corresponding author. E-mail: yaghi@30 AUGUST 2013 VOL 341 SCIENCE Published by AAASThe Chemistry and Applications of Metal-Organic FrameworksHiroyasu Furukawa,1,2Kyle E.Cordova,1,2Michael O’Keeffe,3,4Omar M.Yaghi1,2,4* Crystalline metal-organic frameworks(MOFs)are formed by reticular synthesis,which creates strong bonds between inorganic and organic units.Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability.These characteristics allow the interior of MOFs to be chemically altered for use in gas separation,gas storage,and catalysis,among other applications.The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids.MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.T he past decade has seen explosive growth in the preparation,characterization,andstudy of materials known as metal-organic frameworks(MOFs).These materials are con-structed by joining metal-containing units[sec-ondary building units(SBUs)]with organic linkers, using strong bonds(reticular synthesis)to create open crystalline frameworks with permanent po-rosity(1).The flexibility with which the metal SBUs and organic linkers can be varied has led to thousands of compounds being prepared and studied each year(Figs.1and2).MOFs have ex-ceptional porosity and a wide range of potential uses including gas storage,separations,and ca-talysis(2).In particular,applications in energy technologies such as fuel cells,supercapacitors, and catalytic conversions have made them ob-jects of extensive study,industrial-scale produc-tion,and application(2–4).Among the many developments made in this field,four were particularly important in advanc-ing the chemistry of MOFs:(i)The geometric principle of construction was realized by the link-ing of SBUs with rigid shapes such as squares and octahedra,rather than the simpler node-and-spacer construction of earlier coordination net-works in which single atoms were linked by ditopic coordinating linkers(1).The SBU approach not only led to the identification of a small number of preferred(“default”)topologies that could be targeted in designed syntheses,but also was cen-tral to the achievement of permanent porosity in MOFs(1).(ii)As a natural outcome of the use of SBUs,a large body of work was subsequently reported on the use of the isoreticular principle (varying the size and nature of a structure without changing its underlying topology)in the design of MOFs with ultrahigh porosity and unusuallylarge pore openings(5).(iii)Postsynthetic mod-ification(PSM)of MOFs—incorporating organicunits and metal-organic complexes through re-actions with linkers—has emerged as a powerfultool for changing the reactivity of the pores(e.g.,creating catalytic sites)(6).(iv)Multivariate MOFs(MTV-MOFs),in which multiple organic function-alities are incorporated within a single framework,have provided many opportunities for designingcomplexity within the pores of MOFs in a con-trolled manner(7).Below,we focus on these aspects of MOFchemistry because they are rarely achieved in oth-er materials and because they lead to the previous-ly elusive synthesis of solids by design.Unlikeother extended solids,MOFs maintain their under-lying structure and crystalline order upon expan-sion of organic linkers and inorganic SBUs,aswell as after chemical functionalization,whichgreatly widens the scope of this chemistry.Wereview key developments in these areas and dis-cuss the impact of this chemistry on applicationssuch as gas adsorption and storage,catalysis,andproton conduction.We also discuss the conceptof MTV-MOFs in relation to the sequence of func-tionality arrangement that is influenced by theelectronic and/or steric interactions among thefunctionalities.Highly functional synthetic crys-talline materials can result from the use of suchtechniques to create heterogeneity within MOFstructures.Design of Ultrahigh PorosityDuring the past century,extensive work was doneon crystalline extended structures in which metalions are joined by organic linkers containing Lewisbase–binding atoms such as nitriles and bipyridines(8,9).Although these are extended crystal struc-tures and not large discrete molecules such as poly-mers,they were dubbed coordination“polymers”—a term that is still in use today,although we preferthe more descriptive term MOFs,introduced in1995(10)and now widely accepted.Becausethese structures were constructed from long or-ganic linkers,they encompassed void space andtherefore were viewed to have the potential to be1Department of Chemistry,University of California,Berkeley,CA94720,USA.2Materials Sciences Division,Lawrence Berkeley National Laboratory,Berkeley,CA94720,USA.3Department of Chemistry,Arizona State University,Tempe,AZ87240,USA. 4NanoCentury KAIST Institute and Graduate School of Energy,Environment,Water,and Sustainability(World Class Univer-sity),Daejeon305-701,Republic of Korea.*Corresponding author.E-mail:yaghi@ln(No.ofstructures)YearDoubling time9.3 years5.7 years3.9 years2010200520001995199019851980197512108642No.ofMOFstructures7000600050004000300020001000Year2122222199199199199199198198198198198197197197197Total (CSD)Extended (1D, 2D, 3D)MOFs (3D)Fig.1.Metal-organic framework structures(1D,2D,and3D)reported in the Cambridge Struc-tural Database(CSD)from1971to2011.The trend shows a striking increase during this period for all structure types.In particular,the doubling time for the number of3D MOFs(inset)is the highest among all reported metal-organic structures. SCIENCE VOL34130AUGUST20131230444-1BAZn 4O(CO 2)6M 3O 3(CO 2)3 (M = Zn, Mg, Co, Ni, Mn, Fe, and Cu)Ni 4(C 3H 3N 2)8In(C 5HO 4N 2)4Zr 6O 4(OH)4-(CO 2)12Zr 6O 8(CO 2)8M 3O(CO 2)6 (M = Zn, Cr, In, and Ga)M 2(CO 2)4(M = Cu, Zn, Fe, Mo, Cr, Co, and Ru)Zn(C 3H 3N 2)4Na(OH)2(SO 3)3Cu 2(CNS)4H 2BDCH 4DOTH 2BDC-X (X = Br, OH, NO 2, and NH 2)H 2BDC-(X)2(X = Me, Cl, COOH, OC 3H 5, and OC 7H 7)H 4ADBFumaric acidOxalic acidH 4ATC H 3THBTSH 3ImDCDTOAADPH 3BTPTIPA Gly-AlaH 4DH9PhDC H 4DH11PhDCH 3BTCIr(H 2DPBPyDC)(PPy)2+H 6BTETCADCDPBN BPP34C10DAH 3BTB (X = CH)H 3TATB (X = N)H 3BTE (X = C ≡C)H 3BBC (X = C 6H 4)H 6TPBTM (X = CONH)H 6BTEI (X = C ≡C)H 6BTPI (X = C 6H 4)H 6BHEI (X = C ≡C−C ≡C)H 6BTTI (X = (C 6H 4)2)H 6PTEI (X = C 6H 4−C ≡C)H 6TTEI (X = C ≡C-C 6H 4-C ≡C)H 6BNETPI (X = C ≡C−C 6H 4−C ≡C−C ≡C)H 6BHEHPI (X = (C 6H 4−C ≡C)2)COOHCOOHCOOHCOOH COOHCOOHOH HOCOOHCOOHXCOOHCOOHX XCOOHHOOCCOOHHOOC OHOO OHNCOOHHOOCNHOOCCOOHN NH HOOCCOOHNNH N HNNHN SO 3H SO 3HHO 3SOHHOOH NH 2H 2NSSN NNN NNNCOOHHOOCCOOHH N H 2NOCOOHOHCOOHHOCOOHOHHOCOOHCOOHHOOCCOOHX XXCOOHHOOCCOOHNN OH OHClClCOOHHOOCCOOHCOOHCOOHHOOCOOOOOCOOHCOOH OOOOONNCOOHCOOHIr NN+COOHHOOCCOOHXXXCOOHCOOHHOOCCOOHHOOCCOOHXXX Al(OH)(CO 2)2 VO(CO 2)2Fig.2.Inorganic secondary building units (A)and organic linkers (B)referred to in the text.Color code:black,C;red,O;green,N;yellow,S;purple,P;light green,Cl;blue polyhedra,metal ions.Hydrogen atoms are omitted for clarity.AIPA,tris(4-(1H -imidazol-1-yl)phenyl)amine;ADP,adipic acid;TTFTB4–,4,4′,4′′,4′′′-([2,2′-bis(1,3-dithiolylidene)]-4,4′,5,5′-tetrayl)tetrabenzoate.30AUGUST 2013VOL 341SCIENCE 1230444-2REVIEWpermanently porous,as is the case for zeolites.The porosity of these compounds was investigated in the1990s by forcing gas molecules into the crev-ices at high pressure(11).However,proof of per-manent porosity requires measurement of reversible gas sorption isotherms at low pressures and tem-peratures.Nonetheless,as we remarked at that time(12),it was then commonplace to refer to materials as“porous”and“open framework”even though such proof was lacking.The first proof of permanent porosity of MOFs was obtained by mea-surement of nitrogen and carbon dioxide isotherms on layered zinc terephthalate MOF(12).A major advance in the chemistry of MOFs came in1999when the synthesis,x-ray single-crystal structure determination,and low-temperature, low-pressure gas sorption properties were reported for the first robust and highly porous MOF,MOF-5 (13).This archetype solid comprises Zn4O(CO2)6 octahedral SBUs each linked by six chelating 1,4-benzenedicarboxylate(BDC2–)units to give a cubic framework(Fig.2,figs.S2and S3,and tables S1and S2).The architectural robustness of MOF-5allowed for gas sorption measurements, which revealed61%porosity and a Brunauer-Emmett-Teller(BET)surface area of2320m2/g (2900m2/g Langmuir).These values are substan-tially higher than those commonly found for zeo-lites and activated carbon(14).To prepare MOFs with even higher surface area(ultrahigh porosity)requires an increase in storage space per weight of the material.Longer organic linkers provide larger storage space and a greater number of adsorption sites within a given material.However,the large space within the crys-tal framework makes it prone to form interpen-etrating structures(two or more frameworks grow and mutually intertwine together).The most effec-tive way to prevent interpenetration is by making MOFs whose topology inhibits interpenetration because it would require the second framework to have a different topology(15).Additionally, it is important to keep the pore diameter in the micropore range(below2nm)by judicious se-lection of organic linkers in order to maximize the BETsurface area of the framework,because it is known that BET surface areas obtained from isotherms are similar to the geometric surface areas derived from the crystal structure(16).In2004, MOF-177[Zn4O(BTB)2;BTB=4,4′,4′′-benzene-1,3,5-triyl-tribenzoate]was reported with the high-est surface area at that time(BET surface area= 3780m2/g,porosity=83%;Figs.3A and4)(15), which satisfies the above requirements.In2010, the surface area was doubled by MOF-200and MOF-210[Zn4O(BBC)2and(Zn4O)3(BTE)4(BPDC)3, respectively;BBC3–=4,4′,4′′-(benzene-1,3,5-triyl-tris(benzene-4,1-diyl))tribenzoate;BTE= 4,4′,4′′-(benzene-1,3,5-triyl-tris(ethyne-2,1-diyl)) tribenzoate;BPDC=biphenyl-4,4′-dicarboxylate] to produce ultrahigh surface areas(4530m2/g and6240m2/g,respectively)and porosities(90% and89%)(17).An x-ray diffraction study performed on a sin-gle crystal of MOF-5dosed with nitrogen or argon gas identified the adsorption sites within the pores(18).The zinc oxide SBU,the faces,and,sur-prisingly,the edges of the BDC2–linker serve asadsorption sites.This study uncovered the originof the high porosity and has enabled the design ofMOFs with even higher porosities(Fig.4and ta-ble S3).Moreover,it has been reported that ex-panded tritopic linkers based on alkyne rather thanphenylene units should increase the number ofadsorption sites and increase the surface area(19).NU-110[Cu3(BHEHPI);BHEHPI6–=5,5′,5′′-((((benzene-1,3,5-triyltris(benzene-4,1-diyl))tris(ethyne-2,1-diyl))-tris(benzene-4,1-diyl))tris(ethyne-2,1-diyl))triisophthalate],whose organiclinker is replete with such edges,displayed a sur-face area of7140m2/g(Table1)(7,17,20–32).For many practical purposes,such as storinggases,calculating the surface area per volumeis more relevant.By this standard,the value forMOF-5,2200m2/cm3,is among the very bestreported for MOFs(for comparison,the value forNU-110is1600m2/cm3).Note that the externalsurface area of a nanocube with edges measuring3nm would be2000m2/cm3.However,nano-crystallites on this scale with“clean”surfaceswould immediately aggregate,ultimately leavingtheir potential high surface area inaccessible.Expansion of Structures by a Factor of2to17A family of16cubic MOFs—IRMOF-1[alsoknown as MOF-5,which is the parent MOF ofthe isoreticular(IR)series]to IRMOF-16—withthe same underlying topology(isoreticular)wasmade with expanded and variously functionalizedorganic linkers(figs.S2and S3)(1,5).This de-velopment heralded the potential for expandingand functionalizing MOFs for applications in gasstorage and separations.The same work demon-strated that a large number of topologically iden-tical but functionally distinctive structures can bemade.Note that the topology of these isoreticularMOFs is typically represented with a three-lettercode,pcu,which refers to its primitive cubic net(33).One of the smallest isoreticular structuresof MOF-5is Zn4O(fumarate)3(34);one of thelargest is IRMOF-16[Zn4O(TPDC)3;TPDC2–=terphenyl-4,4′′-dicarboxylate](5)(fig.S2).In thisexpansion,the unit cell edge is doubled and itsvolume is increased by a factor of8.The degreeof interpenetration,and thus the porosity and den-sity of these materials,can be controlled by chang-ing the concentration of reactants,temperature,orother experimental conditions(5).The concept of the isoreticular expansion isnot simply limited to cubic(pcu)structures,asillustrated by the expansion of MOF-177to giveMOF-180[Zn4O(BTE)2]and MOF-200,whichuse larger triangular organic linkers(qom net;Fig.3A and fig.S4)(15,17).Contrary to the MOF-5type of expanded framework,expanded structuresof MOF-177are noninterpenetrating despite thehigh porosity of these MOFs(89%and90%forMOF-180and MOF-200,respectively).Theseresults highlight the critical role of selectingtopology.Another MOF of interest is known as HKUST-1[Cu3(BTC)2;BTC3–=benzene-1,3,5-tricarboxylate](35);it is composed of Cu paddlewheel[Cu2(CO2)4]SBUs(Fig.2A)and a tritopic organic linker,BTC3–.Several isoreticular structures have been madeby expansion with TA TB3–[4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzoate],TA TAB3–[4,4′,4′′-((1,3,5-triazine-2,4,6-triyl)tris(azanediyl))tribenzoate],TTCA3–[triphenylene-2,6,10-tricarboxylate],HTB3–[4,4′,4′′-(1,3,3a1,4,6,7,9-heptaazaphenalene-2,5,8-triyl)tribenzoate],and BBC3–linkers(tbonet;Fig.3B,fig.S1and S5,and tables S1andS2)(21,36–39).The cell volume for the largestreported member[MOF-399,Cu3(BBC)2]is17.4times that of HKUST-1.MOF-399has thehighest void fraction(94%)and lowest density(0.126g/cm3)of any MOF reported to date(21).Cu paddlewheel units are also combined withvarious lengths of hexatopic linkers to form an-other isoreticular series.The first example of oneof these MOFs is Zn3(TPBTM)[TPBTM6–=5,5′,5′′-((benzene-1,3,5-tricarbonyl)tris(azanediyl))triisophthalate],which has a ntt net(40).Shortlyafter this report,several isoreticular MOF struc-tures were synthesized(Fig.3C and fig.S6)(19,20,24,41–48):Cu3(TPBTM),Cu3(TDPA T),NOTT-112[Cu3(BTPI)],NOTT-116[also knownas PCN-68;Cu3(PTEI)],PCN-61[Cu3(BTEI)],PCN-66[Cu3(NTEI)],PCN-69[also known asNOTT-119;Cu3(BTTI)],PCN-610[also knownas NU-100;Cu3(TTEI)],NU-108[Cu3(BTETCA)],NU-109[Cu3(BNETPI)],NU-110,and NU-111[Cu3(BHEI)]TDPA T6–=5,5′,5′′-((1,3,5-triazine-2,4,6-triyl)tris(azanediyl))triisophthalate;BTPI6–=5,5′,5′′-(benzene-1,3,5-triyl-tris(benzene-4,1-diyl))triisophthalate;PTEI6–=5,5′,5′′-((benzene-1,3,5-triyl-tris(benzene-4,1-diyl))tris(ethyne-2,1-diyl))triisophthalate;BTEI6–=5,5′,5′′-(benzene-1,3,5-triyl-tris(ethyne-2,1-diyl))triisophthalate;NTEI6–=5,5′,5′′-((nitrilotris(benzene-4,1-diyl))tris(ethyne-2,1-diyl))triisophthalate;BTTI6–=5,5′,5′′-(benzene-1,3,5-triyl-tris(biphenyl-4,4′-diyl))triisophthalate;TTEI6–=5,5′,5′′-(((benzene-1,3,5-triyl-tris(ethyne-2,1-diyl))tris(benzene-4,1-diyl))tris(ethyne-2,1-diyl))triisophthalate;BTETCA6–=5′,5′′′′,5′′′′′′′-(benzene-1,3,5-triyl-tris(ethyne-2,1-diyl))tris(([1,1′:3′,1′′-terphenyl]-4,4′′-dicarboxylate));BNETPI6–=5,5′,5″-(((benzene-1,3,5-triyl-tris(ethyne-2,1-diyl))tris(benzene-4,1-diyl))tris(buta-1,3-diyne-4,1-diyl))triisophthalate;BHEI6–=5,5′,5″-(benzene-1,3,5-triyl-tris(buta-1,3-diyne-4,1-diyl))triisophthalate].Isoreticularmaterials are not necessarily expansions of theoriginal parent MOF,as exemplified by NU-108,because the ntt family has a linker(BTETCA6–)with two branching points and two kinds of links(figs.S1B and S7).A wide variety of metal ions form metal-carboxylate units,and isostructural MOFs can besynthesized by replacing the metal ions in theinorganic SBUs.Indeed,after the appearance ofHKUST-1[Cu3(BTC)2],an isostructural series ofHKUST-1[M3(BTC)2,where M=Zn(II),Fe(II),Mo(II),Cr(II),Ru(II)]was prepared by sever-al groups(fig.S5)(49–53).In the same way as SCIENCE VOL34130AUGUST20131230444-3REVIEWABDCZn 4O(CO 2)6Cu 2(CO 2)4Cu 2(CO 2)4Zn 4O(BTB)2MOF-177 (qom )Cu 3(BTC)2, HKUST -1MOF-199 (tbo )Cu 3(BBC)2,MOF-399 (tbo )Cu 3(TATB)2, PCN-6’ (tbo )Zn 4O(BTE)2MOF-180 (qom )Zn 4O(BBC)2MOF-200 (qom )× 1.820 Å× 2.7Tritopic linker20 Å× 5.5× 17.4Hexatopic linker30 Å× 2.2× 6.0× 6.5× 16.130 ÅTetratopic linkerCu 3(TDPAT) (ntt )Cu 3(NTEI),PCN-66 (ntt )Cu 3(BHEHPI),NU-110 (ntt )Mg 3O 3(CO 2)3Mg 2(DOT), Mg-MOF-74(IRMOF-74-I) (etb )Mg 2(DH11PhDC),IRMOF-74-XI (etb )Mg 2(DH5PhDC),IRMOF-74-V (etb )Tritopic linkerFig. 3.Isoreticular expansion of metal-organic frameworks with qom,tbo,ntt,and etb nets.(A to D )The isoreticular (maintaining same topology)expansion of archetypical metal-organic frameworks resulting from discrete [(A),(B),and (C)]and rod inorganic SBUs (D)combined with tri-,hexa-,and tetratopic organic linkers to obtain MOFs in qom (A),tbo (B),ntt (C),and etb (D)nets,respectively.Each panel shows a scaled comparison of the smallest,medium,and largest crystalline structures of MOFs representative of these nets.The large yellow and green spheres represent the largest sphere that would occupy the cavity.Numbers above each arrow represent the degree of volume expansion from the smallest framework.Color code is same as in Fig.2;hydrogen atoms are omitted for clarity.30AUGUST 2013VOL 341SCIENCE1230444-4REVIEWdiscrete inorganic SBUs,the infinite inorganic rod-type SBUs were also used to synthesize isostructural MOF-74[Zn 2(DOT);DOT =dioxidoterephthalate](54)using divalent metal ions such as Mg,Co,Ni,and Mn (fig.S8)(55).Exceptionally Large Pore AperturesPore openings of MOFs are typically large enough (up to 2nm)to accommodate small molecules,but rarely are they of appropriate size to permit inclusion of large molecules such as proteins.The best way to increase pore apertures is to use infinite rod-shaped SBUs with linkers of arbitrary length providing periodicity in the other two di-mensions,which does not allow for interpene-trating structures.This strategy was implemented by expanding the original phenylene unit of MOF-74[M 2(DOT);M 2+=Zn,Mg]structure (54)to 2,3,4,5,6,7,9,and 11phenylene units [DH2PhDC 4–to DH11PhDC 4–,respectively;Fig.2B,Fig.3D,and figs.S1B and S8](22).Crystal structures revealed that pore apertures for this series of MOF-74struc-tures (termed IRMOF-74-I to IRMOF-74-XI)ranged from 14to 98Å.The presence of the large pore apertures was also confirmed by transmission elec-tron microscopy (TEM)and scanning electron microscopy (SEM)observation as well as argon adsorption measurements of the guest-free mate-rials.As expected,the pore aperture of IRMOF-74-IX is of sufficient size to allow for green fluorescent protein (barrel structure with diameter of 34Åand length of 45Å)to pass into the pores without unfolding.More important,the large pore aperture is of benefit to the surface modification of the pores with various functionalities without sacrificing the porosity (22).An oligoethylene glycol –functionalized IRMOF-74-VII [Mg 2(DH7PhDC-oeg)]allows in-clusion of myoglobin,whereas IRMOF-74-VII with hydrophobic hexyl chains showed a negli-gible amount of inclusion.High Thermal and Chemical StabilityBecause MOFs are composed entirely of strong bonds (e.g.,C-C,C-H,C-O,and M-O),they show high thermal stability ranging from 250°to 500°C (5,56–58).It has been a challenge to make chem-ically stable MOFs because of their susceptibility to link-displacement reactions when treated with solvents over extended periods of time (days).The first example of a MOF with exceptional chemical stability is zeolitic imidazolate framework –8[ZIF-8,Zn(MIm)2;MIm –=2-methylimidazolate],which was reported in 2006(56).ZIF-8is unaltered after immersion in boiling methanol,benzene,and water for up to 7days,and in concentrated sodium hydroxide at 100°C for 24hours.201220102008200620041999010002000300040005000600070008000Typical conventionalporous materialsMOFsZ e o l i t e s (0.30)S i l i c a s (1.15)C a r b o n s (0.60)MIL-101(2.15)MIL-101 (2.00)MOF-177 (1.59)NOTT-119 (2.35)MOF-210 (3.60)NU-100 (2.82)NU-110(4.40)UMCM-2(2.32)DUT-49(2.91)MOF-5(1.04)MOF-5 (1.20)MOF-5(1.56)MOF-177 (2.00)IRMOF-20 (1.53)MOF-5 (1.48)U M C M -1 (2.24)P C N -6 (1.41)M I L -100 (1.10)M O F -200 (3.59)B i o -M O F -100 (4.30)N O T T -112 (1.59)D U T -23(C o ) (2.03)Fig.4.Progress in the synthesis of ultrahigh-porosity MOFs.BET surface areas of MOFs and typical conventional materials were estimated from gas adsorption measurements.The values in parentheses represent the pore volume (cm 3/g)of these materials.Table 1.Typical properties and applications of metal-organic frameworks.Metal-organic frameworks exhibiting the lowest and highest values for the indicated property,and those reported first for selected applications,are shown.Property or applicationCompound Achieved value or year of reportReference Lowest reported value DensityMOF-3990.126g/cm 3(21)Highest reported value Pore apertureIRMOF-74-XI 98Å(22)Number of organic linkers MTV-MOF-58(7)Degrees of interpenetration Ag 6(OH)2(H 2O)4(TIPA)554(23)BET surface area NU-1107140m 2/g (20)Pore volumeNU-110 4.40cm 3/g (20)Excess hydrogen uptake (77K,56bar)NU-1009.0wt%(24)Excess methane uptake (290K,35bar)PCN-14212mg/g (25)Excess carbon dioxide uptake (298K,50bar)MOF-2002347mg/g (17)Proton conductivity (98%relative humidity,25°C)(NH 4)2(ADP)[Zn 2(oxalate)3]·3H 2O8×10−3S/cm (26)Charge mobilityZn 2(TTFTB)0.2cm 2/V·s (27)Lithium storage capacity (after 60cycles)Zn 3(HCOO)6560mAh/g(28)Earliest reportCatalysis by a MOFCd(BPy)2(NO 3)21994(29)Gas adsorption isotherm and permanent porosity MOF-21998(12)Asymmetric catalysis with a homochiral MOF POST-12000(31)Production of open metal site MOF-112000(30)PSM on the organic linkerPOST-12000(31)Use of a MOF for magnetic resonance imagingMOF-732008(32) SCIENCE VOL 34130AUGUST 20131230444-5REVIEWMOFs based on the Zr(IV)cuboctahedral SBU (Fig.2A)also show high chemical stability;UiO-66[Zr 6O 4(OH)4(BDC)6]and its NO 2-and Br-functionalized derivatives demonstrated high acid (HCl,pH =1)and base resistance (NaOH,pH =14)(57,58).The stability also remains when tetratopic organic linkers are used;both MOF-525[Zr 6O 4(OH)4(TpCPP-H 2)3;TpCPP =tetra-para -carboxyphenylporphyrin]and 545[Zr 6O 8(TpCPP-H 2)2]are chemically stable in methanol,water,and acidic conditions for 12hours (59).Furthermore,a pyrazolate-bridged MOF [Ni 3(BTP)2;BTP 3–=4,4′,4″-(benzene-1,3,5-triyl)tris(pyrazol-1-ide)]is stable for 2weeks in a wide range of aqueous solutions (pH =2to 14)at 100°C (60).The high chemical stability observed in these MOFs is expected to enhance their per-formance in the capture of carbon dioxide from humid flue gas and extend MOFs ’applications to water-containing processes.Postsynthetic Modification (PSM):Crystals as MoleculesThe first very simple,but far from trivial,example of PSM was with the Cu paddlewheel carboxylate MOF-11[Cu 2(A TC);A TC 4–=adamantane-1,3,5,7-tetracarboxylate](30).As-prepared Cu atoms are bonded to four carboxylate O atoms,and the co-ordination shell is completed typically with coor-dinated water (Fig.2A).Subsequent removal of the water from the immobilized Cu atom leaves a coordinatively unsaturated site (“open metal site ”).Many other MOFs with such sites have now been generated and have proved to be exceptionally favorable for selective gas uptake and catalysis (61–63).The first demonstration of PSM on the or-ganic link of a MOF was reported in 2000for a homochiral MOF,POST-1[Zn 3(m 3-O)(D-PTT)6;D-PTT –=(4S ,5S )-2,2-dimethyl-5-(pyridin-4-ylcarbamoyl)-1,3-dioxolane-4-carboxylate](31).It involved N -alkylation of dangling pyridyl func-tionalities with iodomethane and 1-iodohexane to produce N -alkylated pyridinium ions exposed to the pore cavity.More recently,PSM was applied to the dan-gling amine group of IRMOF-3[Zn 4O(BDC-NH 2)3]crystals (6).The MOF was submerged in a dichloromethane solution containing acetic anhy-dride to give the amide derivative in >80%yield.Since then,a large library of organic reactions have been used to covalently functionalize MOF backbones (table S4)(64,65).UMCM-1-NH 2[(Zn 4O)3(BDC-NH 2)3(BTB)4]was also acylated with benzoic anhydride to produce the corresponding amide functionality within the pores (66).The structures of both IRMOF-3and UMCM-1-NH 2after modification showed increased hydrogen uptake relative to the parent MOFs,even though there was a reduction in overall surface area (66).PSM has also been used to dangle catalytically active centers within the pores.In an example reported in 2005,a Cd-based MOF built from 6,6′-dichloro-4,4′-di(pyridin-4-yl)-[1,1′-binaphthalene]-2,2′-diol (DCDPBN),[CdCl 2(DCDPBN)],used orthogonal dihydroxy functionalities to coordinate titanium isopropoxide [Ti(O i Pr)4],thus yielding a highly active,enantio-selective asymmetric Lewis acid catalyst (67).UMCM-1-NH 2was also functionalized in such a manner to incorporate salicylate chelating groups,which were subsequently metallated with Fe(III)and used as a catalyst for Mukaiyama aldol reac-tions over multiple catalytic cycles without loss of activity or crystallinity (68).Indeed,the remarkable retention of MOF crystallinity and porosity after undergoing the transformation reactions clearly dem-onstrates the use of MOF crystals as molecules (69).Catalytic Transformations Within the Pores The high surface areas,tunable pore metrics,and high density of active sites within the very open structures of MOFs offer many advantages to their use in catalysis (table S5).MOFs can be used to support homogeneous catalysts,stabi-lize short-lived catalysts,perform size selectiv-ity,and encapsulate catalysts within their pores (70).The first example of catalysis in an ex-tended framework,reported in 1994,involved the cyanosilylation of aldehydes in a Cd-based frame-work [Cd(BPy)2(NO 3)2;BPy =4,4′-bipyridine]as a result of axial ligand removal (29).This study also highlighted the benefits of MOFs as size-selective catalysts by excluding large sub-strates from the pores.In 2006,it was shown that removal of solvent from HKUST-1exposes open metal sites that may act as Lewis acid catalysts (71).MIL-101[Cr 3X(H 2O)2O(BDC)3;X =F,OH]and Mn-BTT {Mn 3[(Mn 4Cl)3(BTT)8]2;BTT 3–=5,5′,5″-(benzene-1,3,5-triyl)tris(tetrazol-2-ide)}have also been iden-tified as Lewis acid catalysts in which the metal oxide unit functions as the catalytic site upon lig-and removal (62,72).In addition,alkane oxida-tion,alkene oxidation,and oxidative coupling reactions have also been reported;they all rely on the metal sites within the SBUs for catalytic ac-tivity (73–75).The study of methane oxidation in vanadium-based MOF-48{VO[BDC-(Me)2];Me =methyl}is promising because the catalytic turnover and yield for this oxidation far exceed those of the analogous homogeneous catalysts (73).One early example of the use of a MOF as a het-erogeneous catalyst is PIZA-3[Mn 2(TpCPP)2Mn 3],which contains a metalloporphyrin as part of the framework (76).PIZA-3is capable of hydrox-ylating alkanes and catalyzes the epoxidation of olefins.Schiff-base and binaphthyl metal complexes have also been incorporated into MOFs to achieve olefin epoxidation and diethyl zinc (ZnEt 2)addi-tions to aromatic aldehydes,respectively (67,77).The incorporation of porphyrin units within the pores of MOFs can be accomplished during the synthesis (a “ship-in-a-bottle ”approach that cap-tures the units as the pores form),as illustrated for the zeolite-like MOF rho -ZMOF [In(HImDC)2·X;HImDC 2–=imidazoledicarboxylate,X –=coun-teranion](78).The pores of this framework accom-modate high porphyrin loadings,and the pore aperture is small enough to prevent porphyrin fromleaching out of the MOF.The porphyrin metal sites were subsequently metallated and used for the oxidation of cyclohexane.The same approach has been applied to several other systems in which polyoxometalates are encapsulated within MIL-101(Cr)and HKUST-1for applications in the oxidation of alkenes and the hydrolysis of esters in excess water (79,80).Integration of nanoparticles for catalysis by PSM has been carried out to enhance particle stability or to produce uniform size distributions.Palladium nanoparticles were incorporated with-in MIL-101(Cr)for cross-coupling reactions (81,82).Most recently,a bifunctional catalytic MOF {Zr 6O 4(OH)4[Ir(DPBPyDC)(PPy)2·X]6;DPBPyDC 2–=4,4′-([2,2′-bipyridine]-5,5′-diyl)dibenzoate,PPy =2-phenylpyridine}capable of water-splitting reactions was reported (83).This MOF uses the organic linker and an encapsulated nanoparticle to transfer an electron to a proton in solution,leading to hydrogen evolution.Gas Adsorption for Alternative Fuels and Separations for Clean AirMuch attention is being paid to increasing the storage of fuel gases such as hydrogen and meth-ane under practical conditions.The first study of hydrogen adsorption was reported in 2003for MOF-5(84).This study confirmed the potential of MOFs for application to hydrogen adsorption,which has led to the reporting of hydrogen ad-sorption data for hundreds of MOFs (85).In gen-eral,the functionality of organic linkers has little influence on hydrogen adsorption (86),whereas increasing the pore volume and surface area of MOFs markedly enhances the gravimetric hydro-gen uptake at 77K and high pressure,as exem-plified by the low-density materials:NU-100and MOF-210exhibit hydrogen adsorption as high as 7.9to 9.0weight percent (wt%)at 56bar for both MOFs and 15wt%at 80bar for MOF-210(17,24).However,increasing the surface area is not always an effective tool for increasing the volumetric hydrogen adsorption,which can be accomplished by increasing the adsorption enthalpy of hy-drogen (Q st )(87).In this context,open metal sites have been suggested and used to enhance the hydrogen uptake capacity and to improve Q st (61,85).Two MOFs with this characteristic,Zn 3(BDC)3[Cu(Pyen)][Pyen 2–=5,5′-((1E ,1′E )-(ethane-1,2-diyl-bis(azanylylidene))bis(methanylylidene))bis(3-methylpyridin-4-ol)]and Ni-MOF-74,have the highest reported initial Q st values:15.1kJ/mol and 12.9kJ/mol,respectively (58,88).Metal impreg-nation has also been suggested by computation as a method for increasing the Q st values (89).Experiments along these lines show that dop-ing MOFs with alkali metal cations yields only modest enhancements in the total hydrogen up-take and Q st values (90,91).Although some chal-lenges remain in meeting the U.S.Department of Energy (DOE)system targets (5.5wt%and 40g/liter at –40°to 60°C below 100bar)for hy-drogen adsorption (85),Mercedes-Benz has al-ready deployed MOF hydrogen fuel tanks in a30AUGUST 2013VOL 341SCIENCE1230444-6REVIEW。

金纳米簇金属有机骨架

金纳米簇金属有机骨架English.Gold nanoclusters (Au NCs) are discrete atomically precise subnanometer-sized gold particles with unique physicochemical properties that differ significantly from their bulk counterparts or larger nanoparticles. They have attracted considerable attention due to their intriguing optical, electronic, catalytic, and biological properties, which make them promising candidates for various applications in sensing, catalysis, bioimaging, and theranostics. Metal-organic frameworks (MOFs) are a class of highly porous crystalline materials constructed from inorganic metal ions or clusters coordinated to organic ligands. MOFs have gained significant interest due to their exceptional structural diversity, tunable porosity, and diverse functionalities. The combination of Au NCs and MOFs has emerged as a promising strategy to create multifunctional hybrid materials with synergistic properties.The integration of Au NCs into MOFs offers several advantages. Firstly, Au NCs can serve as active siteswithin the MOFs, enhancing their catalytic activity, electrochemical performance, and sensing capabilities. The small size and high surface area of Au NCs provide abundant active sites for catalytic reactions, while the well-defined structure and composition of Au NCs enable precise control over their catalytic properties. Secondly, Au NCs can enhance the optical properties of MOFs, leading to improved light absorption, emission, and sensing performance. The localized surface plasmon resonance (LSPR) of Au NCs can interact with light, resulting in enhanced light scattering and absorption, which can be exploited for sensing applications. Thirdly, Au NCs can improve the stability and functionality of MOFs. The incorporation of Au NCs into MOFs can enhance their thermal, chemical, and mechanical stability, making them more suitable for practical applications.The synthesis of Au NC@MOF composites can be achieved through various methods, including direct synthesis, post-synthetic modification, and in situ growth. Direct synthesis involves the simultaneous formation of Au NCs and MOFs in a single step, while post-synthetic modification involves the introduction of Au NCs into pre-synthesized MOFs. In situ growth refers to the formation of Au NCs within the pores or on the surface of MOFs during the MOF synthesis process. The choice of synthesis method depends on the desired properties and applications of the resulting Au NC@MOF composites.应用。